Fix key reload

The internal updateInterfaces() function expects iFaceDiscover to not
be nil

.github/workflows/docs-ack.yml

@@ -16,19 +16,29 @@ jobs:
     steps:
       - name: Read PR body
         id: body
+        shell: bash
         run: |
-          BODY=$(jq -r '.pull_request.body // ""' "$GITHUB_EVENT_PATH")
-          echo "body<<EOF" >> $GITHUB_OUTPUT
-          echo "$BODY" >> $GITHUB_OUTPUT
-          echo "EOF" >> $GITHUB_OUTPUT
+          set -euo pipefail
+          BODY_B64=$(jq -r '.pull_request.body // "" | @base64' "$GITHUB_EVENT_PATH")
+          {
+            echo "body_b64=$BODY_B64"
+          } >> "$GITHUB_OUTPUT"
 
       - name: Validate checkbox selection
         id: validate
+        shell: bash
+        env:
+          BODY_B64: ${{ steps.body.outputs.body_b64 }}
         run: |
-          body='${{ steps.body.outputs.body }}'
+          set -euo pipefail
+          if ! body="$(printf '%s' "$BODY_B64" | base64 -d)"; then
+            echo "::error::Failed to decode PR body from base64. Data may be corrupted or missing."
+            exit 1
+          fi
+
+          added_checked=$(printf '%s' "$body" | grep -Ei '^[[:space:]]*-\s*\[x\]\s*I added/updated documentation' | wc -l | tr -d '[:space:]' || true)
+          noneed_checked=$(printf '%s' "$body" | grep -Ei '^[[:space:]]*-\s*\[x\]\s*Documentation is \*\*not needed\*\*' | wc -l | tr -d '[:space:]' || true)
 
-          added_checked=$(printf "%s" "$body" | grep -E '^- \[x\] I added/updated documentation' -i | wc -l | tr -d ' ')
-          noneed_checked=$(printf "%s" "$body" | grep -E '^- \[x\] Documentation is \*\*not needed\*\*' -i | wc -l | tr -d ' ')
 
           if [ "$added_checked" -eq 1 ] && [ "$noneed_checked" -eq 1 ]; then
             echo "::error::Choose exactly one: either 'docs added' OR 'not needed'."
@@ -41,30 +51,35 @@ jobs:
           fi
 
           if [ "$added_checked" -eq 1 ]; then
-            echo "mode=added" >> $GITHUB_OUTPUT
+            echo "mode=added" >> "$GITHUB_OUTPUT"
           else
-            echo "mode=noneed" >> $GITHUB_OUTPUT
+            echo "mode=noneed" >> "$GITHUB_OUTPUT"
           fi
 
       - name: Extract docs PR URL (when 'docs added')
         if: steps.validate.outputs.mode == 'added'
         id: extract
+        shell: bash
+        env:
+          BODY_B64: ${{ steps.body.outputs.body_b64 }}
         run: |
-          body='${{ steps.body.outputs.body }}'
+          set -euo pipefail
+          body="$(printf '%s' "$BODY_B64" | base64 -d)"
 
           # Strictly require HTTPS and that it's a PR in netbirdio/docs
-          # Examples accepted:
-          #   https://github.com/netbirdio/docs/pull/1234
-          url=$(printf "%s" "$body" | grep -Eo 'https://github\.com/netbirdio/docs/pull/[0-9]+' | head -n1 || true)
+          # e.g., https://github.com/netbirdio/docs/pull/1234
+          url="$(printf '%s' "$body" | grep -Eo 'https://github\.com/netbirdio/docs/pull/[0-9]+' | head -n1 || true)"
 
-          if [ -z "$url" ]; then
+          if [ -z "${url:-}" ]; then
             echo "::error::You checked 'docs added' but didn't include a valid HTTPS PR link to netbirdio/docs (e.g., https://github.com/netbirdio/docs/pull/1234)."
             exit 1
           fi
 
-          pr_number=$(echo "$url" | sed -E 's#.*/pull/([0-9]+)$#\1#')
-          echo "url=$url" >> $GITHUB_OUTPUT
-          echo "pr_number=$pr_number" >> $GITHUB_OUTPUT
+          pr_number="$(printf '%s' "$url" | sed -E 's#.*/pull/([0-9]+)$#\1#')"
+          {
+            echo "url=$url"
+            echo "pr_number=$pr_number"
+          } >> "$GITHUB_OUTPUT"
 
       - name: Verify docs PR exists (and is open or merged)
         if: steps.validate.outputs.mode == 'added'

.github/workflows/golang-test-freebsd.yml

@@ -25,8 +25,7 @@ jobs:
           release: "14.2"
           prepare: |
             pkg install -y curl pkgconf xorg
-            LATEST_VERSION=$(curl -s https://go.dev/VERSION?m=text|head -n 1)
-            GO_TARBALL="$LATEST_VERSION.freebsd-amd64.tar.gz"
+            GO_TARBALL="go1.23.12.freebsd-amd64.tar.gz"
             GO_URL="https://go.dev/dl/$GO_TARBALL"
             curl -vLO "$GO_URL"
             tar -C /usr/local -vxzf "$GO_TARBALL"            

.github/workflows/golang-test-linux.yml

@@ -382,6 +382,32 @@ jobs:
         store: [ 'sqlite', 'postgres' ]
     runs-on: ubuntu-22.04
     steps:
+      - name: Create Docker network
+        run: docker network create promnet
+
+      - name: Start Prometheus Pushgateway
+        run: docker run -d --name pushgateway --network promnet -p 9091:9091 prom/pushgateway
+
+      - name: Start Prometheus (for Pushgateway forwarding)
+        run: |
+          echo '
+          global:
+            scrape_interval: 15s
+          scrape_configs:
+            - job_name: "pushgateway"
+              static_configs:
+                - targets: ["pushgateway:9091"]
+          remote_write:
+            - url: ${{ secrets.GRAFANA_URL }}
+              basic_auth:
+                username: ${{ secrets.GRAFANA_USER }}
+                password: ${{ secrets.GRAFANA_API_KEY }}
+          ' > prometheus.yml
+
+          docker run -d --name prometheus --network promnet \
+            -v $PWD/prometheus.yml:/etc/prometheus/prometheus.yml \
+            -p 9090:9090 \
+            prom/prometheus
       - name: Install Go
         uses: actions/setup-go@v5
         with:
@@ -428,9 +454,10 @@ jobs:
           CGO_ENABLED=1 GOARCH=${{ matrix.arch }} \
           NETBIRD_STORE_ENGINE=${{ matrix.store }} \
           CI=true \
+          GIT_BRANCH=${{ github.ref_name }} \
           go test -tags devcert -run=^$ -bench=. \
-          -exec 'sudo --preserve-env=CI,NETBIRD_STORE_ENGINE' \
-          -timeout 20m ./management/... ./shared/management/...
+          -exec 'sudo --preserve-env=CI,NETBIRD_STORE_ENGINE,GIT_BRANCH,GITHUB_RUN_ID' \
+          -timeout 20m ./management/... ./shared/management/... $(go list ./management/... ./shared/management/... | grep -v -e /management/server/http)
 
   api_benchmark:
     name: "Management / Benchmark (API)"
@@ -521,7 +548,7 @@ jobs:
             -run=^$ \
             -bench=. \
             -exec 'sudo --preserve-env=CI,NETBIRD_STORE_ENGINE,GIT_BRANCH,GITHUB_RUN_ID' \
-            -timeout 20m ./management/... ./shared/management/...
+            -timeout 20m ./management/server/http/...
 
   api_integration_test:
     name: "Management / Integration"
@@ -571,4 +598,4 @@ jobs:
           CI=true \
           go test -tags=integration \
           -exec 'sudo --preserve-env=CI,NETBIRD_STORE_ENGINE' \
-          -timeout 20m ./management/... ./shared/management/...
+          -timeout 20m ./management/server/http/...

.github/workflows/golang-test-windows.yml

@@ -63,7 +63,7 @@ jobs:
       - run: PsExec64 -s -w ${{ github.workspace }} C:\hostedtoolcache\windows\go\${{ steps.go.outputs.go-version }}\x64\bin\go.exe env -w GOMODCACHE=${{ env.cache }}
       - run: PsExec64 -s -w ${{ github.workspace }} C:\hostedtoolcache\windows\go\${{ steps.go.outputs.go-version }}\x64\bin\go.exe env -w GOCACHE=${{ env.modcache }}
       - run: PsExec64 -s -w ${{ github.workspace }} C:\hostedtoolcache\windows\go\${{ steps.go.outputs.go-version }}\x64\bin\go.exe mod tidy
-      - run: echo "files=$(go list ./... | ForEach-Object { $_ } | Where-Object { $_ -notmatch '/management' })" >> $env:GITHUB_ENV
+      - run: echo "files=$(go list ./... | ForEach-Object { $_ } | Where-Object { $_ -notmatch '/management' } | Where-Object { $_ -notmatch '/relay' } | Where-Object { $_ -notmatch '/signal' })" >> $env:GITHUB_ENV
 
       - name: test
         run: PsExec64 -s -w ${{ github.workspace }} cmd.exe /c "C:\hostedtoolcache\windows\go\${{ steps.go.outputs.go-version }}\x64\bin\go.exe test -tags=devcert -timeout 10m -p 1 ${{ env.files }} > test-out.txt 2>&1"

.github/workflows/test-infrastructure-files.yml

@@ -83,6 +83,15 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
+      - name: Setup MySQL privileges
+        if: matrix.store == 'mysql'
+        run: |
+          sleep 10
+          mysql -h 127.0.0.1 -u root -pmysqlroot -e "
+            GRANT SYSTEM_VARIABLES_ADMIN ON *.* TO 'netbird'@'%';
+            FLUSH PRIVILEGES;
+          "
+
       - name: cp setup.env
         run: cp infrastructure_files/tests/setup.env infrastructure_files/
 

client/cmd/debug.go

@@ -33,7 +33,7 @@ var (
 var debugCmd = &cobra.Command{
 	Use:   "debug",
 	Short: "Debugging commands",
-	Long:  "Provides commands for debugging and logging control within the NetBird daemon.",
+	Long:  "Commands for debugging and logging within the NetBird daemon.",
 }
 
 var debugBundleCmd = &cobra.Command{

client/cmd/down.go

@@ -14,7 +14,8 @@ import (
 
 var downCmd = &cobra.Command{
 	Use:   "down",
-	Short: "down netbird connections",
+	Short: "Disconnect from the NetBird network",
+	Long:  "Disconnect the NetBird client from the network and management service. This will terminate all active connections with the remote peers.",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		SetFlagsFromEnvVars(rootCmd)
 

client/cmd/login.go

@@ -31,7 +31,8 @@ func init() {
 
 var loginCmd = &cobra.Command{
 	Use:   "login",
-	Short: "login to the NetBird Management Service (first run)",
+	Short: "Log in to the NetBird network",
+	Long:  "Log in to the NetBird network using a setup key or SSO",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		if err := setEnvAndFlags(cmd); err != nil {
 			return fmt.Errorf("set env and flags: %v", err)

client/cmd/logout.go

@@ -14,7 +14,8 @@ import (
 var logoutCmd = &cobra.Command{
 	Use:     "deregister",
 	Aliases: []string{"logout"},
-	Short:   "deregister from the NetBird Management Service and delete peer",
+	Short:   "Deregister from the NetBird management service and delete this peer",
+	Long:    "This command will deregister the current peer from the NetBird management service and all associated configuration. Use with caution as this will remove the peer from the network.",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		SetFlagsFromEnvVars(rootCmd)
 

client/cmd/networks.go

@@ -15,7 +15,7 @@ var appendFlag bool
 var networksCMD = &cobra.Command{
 	Use:     "networks",
 	Aliases: []string{"routes"},
-	Short:   "Manage networks",
+	Short:   "Manage connections to NetBird Networks and Resources",
 	Long:    `Commands to list, select, or deselect networks. Replaces the "routes" command.`,
 }
 

client/cmd/profile.go

@@ -16,13 +16,13 @@ import (
 
 var profileCmd = &cobra.Command{
 	Use:   "profile",
-	Short: "manage NetBird profiles",
-	Long:  `Manage NetBird profiles, allowing you to list, switch, and remove profiles.`,
+	Short: "Manage NetBird client profiles",
+	Long:  `Commands to list, add, remove, and switch profiles. Profiles allow you to maintain different accounts in one client app.`,
 }
 
 var profileListCmd = &cobra.Command{
 	Use:     "list",
-	Short:   "list all profiles",
+	Short:   "List all profiles",
 	Long:    `List all available profiles in the NetBird client.`,
 	Aliases: []string{"ls"},
 	RunE:    listProfilesFunc,
@@ -30,7 +30,7 @@ var profileListCmd = &cobra.Command{
 
 var profileAddCmd = &cobra.Command{
 	Use:   "add <profile_name>",
-	Short: "add a new profile",
+	Short: "Add a new profile",
 	Long:  `Add a new profile to the NetBird client. The profile name must be unique.`,
 	Args:  cobra.ExactArgs(1),
 	RunE:  addProfileFunc,
@@ -38,16 +38,16 @@ var profileAddCmd = &cobra.Command{
 
 var profileRemoveCmd = &cobra.Command{
 	Use:   "remove <profile_name>",
-	Short: "remove a profile",
-	Long:  `Remove a profile from the NetBird client. The profile must not be active.`,
+	Short: "Remove a profile",
+	Long:  `Remove a profile from the NetBird client. The profile must not be inactive.`,
 	Args:  cobra.ExactArgs(1),
 	RunE:  removeProfileFunc,
 }
 
 var profileSelectCmd = &cobra.Command{
 	Use:   "select <profile_name>",
-	Short: "select a profile",
-	Long:  `Select a profile to be the active profile in the NetBird client. The profile must exist.`,
+	Short: "Select a profile",
+	Long:  `Make the specified profile active. This will switch the client to use the selected profile's configuration.`,
 	Args:  cobra.ExactArgs(1),
 	RunE:  selectProfileFunc,
 }

client/cmd/root.go

@@ -39,6 +39,7 @@ const (
 	extraIFaceBlackListFlag  = "extra-iface-blacklist"
 	dnsRouteIntervalFlag     = "dns-router-interval"
 	enableLazyConnectionFlag = "enable-lazy-connection"
+	mtuFlag                  = "mtu"
 )
 
 var (
@@ -72,7 +73,9 @@ var (
 	anonymizeFlag           bool
 	dnsRouteInterval        time.Duration
 	lazyConnEnabled         bool
+	mtu                     uint16
 	profilesDisabled        bool
+	updateSettingsDisabled  bool
 
 	rootCmd = &cobra.Command{
 		Use:          "netbird",

client/cmd/root_test.go

@@ -54,6 +54,7 @@ func TestSetFlagsFromEnvVars(t *testing.T) {
 	cmd.PersistentFlags().StringVar(&interfaceName, interfaceNameFlag, iface.WgInterfaceDefault, "WireGuard interface name")
 	cmd.PersistentFlags().BoolVar(&rosenpassEnabled, enableRosenpassFlag, false, "Enable Rosenpass feature Rosenpass.")
 	cmd.PersistentFlags().Uint16Var(&wireguardPort, wireguardPortFlag, iface.DefaultWgPort, "WireGuard interface listening port")
+	cmd.PersistentFlags().Uint16Var(&mtu, mtuFlag, iface.DefaultMTU, "Set MTU (Maximum Transmission Unit) for the WireGuard interface")
 
 	t.Setenv("NB_EXTERNAL_IP_MAP", "abc,dec")
 	t.Setenv("NB_INTERFACE_NAME", "test-name")

client/cmd/service.go

@@ -19,7 +19,7 @@ import (
 
 var serviceCmd = &cobra.Command{
 	Use:   "service",
-	Short: "manages NetBird service",
+	Short: "Manage the NetBird daemon service",
 }
 
 var (
@@ -42,7 +42,8 @@ func init() {
 	}
 
 	serviceCmd.AddCommand(runCmd, startCmd, stopCmd, restartCmd, svcStatusCmd, installCmd, uninstallCmd, reconfigureCmd)
-	serviceCmd.PersistentFlags().BoolVar(&profilesDisabled, "disable-profiles", false, "Disables profiles feature. If enabled, the client will not be able to change or edit any profile.")
+	serviceCmd.PersistentFlags().BoolVar(&profilesDisabled, "disable-profiles", false, "Disables profiles feature. If enabled, the client will not be able to change or edit any profile. To persist this setting, use: netbird service install --disable-profiles")
+	serviceCmd.PersistentFlags().BoolVar(&updateSettingsDisabled, "disable-update-settings", false, "Disables update settings feature. If enabled, the client will not be able to change or edit any settings. To persist this setting, use: netbird service install --disable-update-settings")
 
 	rootCmd.PersistentFlags().StringVarP(&serviceName, "service", "s", defaultServiceName, "Netbird system service name")
 	serviceEnvDesc := `Sets extra environment variables for the service. ` +

client/cmd/service_controller.go

@@ -61,7 +61,7 @@ func (p *program) Start(svc service.Service) error {
 			}
 		}
 
-		serverInstance := server.New(p.ctx, util.FindFirstLogPath(logFiles), configPath, profilesDisabled)
+		serverInstance := server.New(p.ctx, util.FindFirstLogPath(logFiles), configPath, profilesDisabled, updateSettingsDisabled)
 		if err := serverInstance.Start(); err != nil {
 			log.Fatalf("failed to start daemon: %v", err)
 		}

client/cmd/service_installer.go

@@ -49,6 +49,14 @@ func buildServiceArguments() []string {
 		args = append(args, "--log-file", logFile)
 	}
 
+	if profilesDisabled {
+		args = append(args, "--disable-profiles")
+	}
+
+	if updateSettingsDisabled {
+		args = append(args, "--disable-update-settings")
+	}
+
 	return args
 }
 
@@ -99,7 +107,7 @@ func createServiceConfigForInstall() (*service.Config, error) {
 
 var installCmd = &cobra.Command{
 	Use:   "install",
-	Short: "installs NetBird service",
+	Short: "Install NetBird service",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		if err := setupServiceCommand(cmd); err != nil {
 			return err

client/cmd/ssh.go

@@ -40,7 +40,7 @@ var sshCmd = &cobra.Command{
 
 		return nil
 	},
-	Short: "connect to a remote SSH server",
+	Short: "Connect to a remote SSH server",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		SetFlagsFromEnvVars(rootCmd)
 		SetFlagsFromEnvVars(cmd)

client/cmd/status.go

@@ -32,7 +32,8 @@ var (
 
 var statusCmd = &cobra.Command{
 	Use:   "status",
-	Short: "status of the Netbird Service",
+	Short: "Display NetBird client status",
+	Long:  "Display the current status of the NetBird client, including connection status, peer information, and network details.",
 	RunE:  statusFunc,
 }
 

client/cmd/testutil_test.go

@@ -9,32 +9,31 @@ import (
 	"github.com/golang/mock/gomock"
 	"github.com/stretchr/testify/require"
 	"go.opentelemetry.io/otel"
+	"google.golang.org/grpc"
 
+	"github.com/netbirdio/management-integrations/integrations"
+	clientProto "github.com/netbirdio/netbird/client/proto"
+	client "github.com/netbirdio/netbird/client/server"
+	"github.com/netbirdio/netbird/management/internals/server/config"
+	mgmt "github.com/netbirdio/netbird/management/server"
 	"github.com/netbirdio/netbird/management/server/activity"
+	"github.com/netbirdio/netbird/management/server/groups"
 	"github.com/netbirdio/netbird/management/server/integrations/port_forwarding"
+	"github.com/netbirdio/netbird/management/server/peers"
 	"github.com/netbirdio/netbird/management/server/permissions"
 	"github.com/netbirdio/netbird/management/server/settings"
 	"github.com/netbirdio/netbird/management/server/store"
 	"github.com/netbirdio/netbird/management/server/telemetry"
 	"github.com/netbirdio/netbird/management/server/types"
-
-	"github.com/netbirdio/netbird/util"
-
-	"google.golang.org/grpc"
-
-	"github.com/netbirdio/management-integrations/integrations"
-
-	clientProto "github.com/netbirdio/netbird/client/proto"
-	client "github.com/netbirdio/netbird/client/server"
 	mgmtProto "github.com/netbirdio/netbird/shared/management/proto"
-	mgmt "github.com/netbirdio/netbird/management/server"
 	sigProto "github.com/netbirdio/netbird/shared/signal/proto"
 	sig "github.com/netbirdio/netbird/signal/server"
+	"github.com/netbirdio/netbird/util"
 )
 
 func startTestingServices(t *testing.T) string {
 	t.Helper()
-	config := &types.Config{}
+	config := &config.Config{}
 	_, err := util.ReadJson("../testdata/management.json", config)
 	if err != nil {
 		t.Fatal(err)
@@ -69,7 +68,7 @@ func startSignal(t *testing.T) (*grpc.Server, net.Listener) {
 	return s, lis
 }
 
-func startManagement(t *testing.T, config *types.Config, testFile string) (*grpc.Server, net.Listener) {
+func startManagement(t *testing.T, config *config.Config, testFile string) (*grpc.Server, net.Listener) {
 	t.Helper()
 
 	lis, err := net.Listen("tcp", ":0")
@@ -88,15 +87,20 @@ func startManagement(t *testing.T, config *types.Config, testFile string) (*grpc
 	if err != nil {
 		return nil, nil
 	}
-	iv, _ := integrations.NewIntegratedValidator(context.Background(), eventStore)
 
-	metrics, err := telemetry.NewDefaultAppMetrics(context.Background())
-	require.NoError(t, err)
 	ctrl := gomock.NewController(t)
 	t.Cleanup(ctrl.Finish)
 
-	settingsMockManager := settings.NewMockManager(ctrl)
 	permissionsManagerMock := permissions.NewMockManager(ctrl)
+	peersmanager := peers.NewManager(store, permissionsManagerMock)
+
+	iv, _ := integrations.NewIntegratedValidator(context.Background(), peersmanager, eventStore)
+
+	metrics, err := telemetry.NewDefaultAppMetrics(context.Background())
+	require.NoError(t, err)
+
+	settingsMockManager := settings.NewMockManager(ctrl)
+	groupsManager := groups.NewManagerMock()
 
 	settingsMockManager.EXPECT().
 		GetSettings(gomock.Any(), gomock.Any(), gomock.Any()).
@@ -108,7 +112,7 @@ func startManagement(t *testing.T, config *types.Config, testFile string) (*grpc
 		t.Fatal(err)
 	}
 
-	secretsManager := mgmt.NewTimeBasedAuthSecretsManager(peersUpdateManager, config.TURNConfig, config.Relay, settingsMockManager)
+	secretsManager := mgmt.NewTimeBasedAuthSecretsManager(peersUpdateManager, config.TURNConfig, config.Relay, settingsMockManager, groupsManager)
 	mgmtServer, err := mgmt.NewServer(context.Background(), config, accountManager, settingsMockManager, peersUpdateManager, secretsManager, nil, nil, nil, &mgmt.MockIntegratedValidator{})
 	if err != nil {
 		t.Fatal(err)
@@ -134,7 +138,7 @@ func startClientDaemon(
 	s := grpc.NewServer()
 
 	server := client.New(ctx,
-		"", "", false)
+		"", "", false, false)
 	if err := server.Start(); err != nil {
 		t.Fatal(err)
 	}

client/cmd/up.go

@@ -53,7 +53,8 @@ var (
 
 	upCmd = &cobra.Command{
 		Use:   "up",
-		Short: "install, login and start NetBird client",
+		Short: "Connect to the NetBird network",
+		Long:  "Connect to the NetBird network using the provided setup key or SSO auth. This command will bring up the WireGuard interface, connect to the management server, and establish peer-to-peer connections with other peers in the network if required.",
 		RunE:  upFunc,
 	}
 )
@@ -62,6 +63,7 @@ func init() {
 	upCmd.PersistentFlags().BoolVarP(&foregroundMode, "foreground-mode", "F", false, "start service in foreground")
 	upCmd.PersistentFlags().StringVar(&interfaceName, interfaceNameFlag, iface.WgInterfaceDefault, "WireGuard interface name")
 	upCmd.PersistentFlags().Uint16Var(&wireguardPort, wireguardPortFlag, iface.DefaultWgPort, "WireGuard interface listening port")
+	upCmd.PersistentFlags().Uint16Var(&mtu, mtuFlag, iface.DefaultMTU, "Set MTU (Maximum Transmission Unit) for the WireGuard interface")
 	upCmd.PersistentFlags().BoolVarP(&networkMonitor, networkMonitorFlag, "N", networkMonitor,
 		`Manage network monitoring. Defaults to true on Windows and macOS, false on Linux and FreeBSD. `+
 			`E.g. --network-monitor=false to disable or --network-monitor=true to enable.`,
@@ -356,6 +358,11 @@ func setupSetConfigReq(customDNSAddressConverted []byte, cmd *cobra.Command, pro
 		req.WireguardPort = &p
 	}
 
+	if cmd.Flag(mtuFlag).Changed {
+		m := int64(mtu)
+		req.Mtu = &m
+	}
+
 	if cmd.Flag(networkMonitorFlag).Changed {
 		req.NetworkMonitor = &networkMonitor
 	}
@@ -435,6 +442,13 @@ func setupConfig(customDNSAddressConverted []byte, cmd *cobra.Command, configFil
 		ic.WireguardPort = &p
 	}
 
+	if cmd.Flag(mtuFlag).Changed {
+		if err := iface.ValidateMTU(mtu); err != nil {
+			return nil, err
+		}
+		ic.MTU = &mtu
+	}
+
 	if cmd.Flag(networkMonitorFlag).Changed {
 		ic.NetworkMonitor = &networkMonitor
 	}
@@ -532,6 +546,14 @@ func setupLoginRequest(providedSetupKey string, customDNSAddressConverted []byte
 		loginRequest.WireguardPort = &wp
 	}
 
+	if cmd.Flag(mtuFlag).Changed {
+		if err := iface.ValidateMTU(mtu); err != nil {
+			return nil, err
+		}
+		m := int64(mtu)
+		loginRequest.Mtu = &m
+	}
+
 	if cmd.Flag(networkMonitorFlag).Changed {
 		loginRequest.NetworkMonitor = &networkMonitor
 	}

client/cmd/version.go

@@ -9,7 +9,7 @@ import (
 var (
 	versionCmd = &cobra.Command{
 		Use:   "version",
-		Short: "prints NetBird version",
+		Short: "Print the NetBird's client application version",
 		Run: func(cmd *cobra.Command, args []string) {
 			cmd.SetOut(cmd.OutOrStdout())
 			cmd.Println(version.NetbirdVersion())

client/firewall/iptables/acl_linux.go

@@ -85,7 +85,7 @@ func (m *aclManager) AddPeerFiltering(
 ) ([]firewall.Rule, error) {
 	chain := chainNameInputRules
 
-	ipsetName = transformIPsetName(ipsetName, sPort, dPort)
+	ipsetName = transformIPsetName(ipsetName, sPort, dPort, action)
 	specs := filterRuleSpecs(ip, string(protocol), sPort, dPort, action, ipsetName)
 
 	mangleSpecs := slices.Clone(specs)
@@ -135,7 +135,14 @@ func (m *aclManager) AddPeerFiltering(
 		return nil, fmt.Errorf("rule already exists")
 	}
 
-	if err := m.iptablesClient.Append(tableFilter, chain, specs...); err != nil {
+	// Insert DROP rules at the beginning, append ACCEPT rules at the end
+	if action == firewall.ActionDrop {
+		// Insert at the beginning of the chain (position 1)
+		err = m.iptablesClient.Insert(tableFilter, chain, 1, specs...)
+	} else {
+		err = m.iptablesClient.Append(tableFilter, chain, specs...)
+	}
+	if err != nil {
 		return nil, err
 	}
 
@@ -388,17 +395,25 @@ func actionToStr(action firewall.Action) string {
 	return "DROP"
 }
 
-func transformIPsetName(ipsetName string, sPort, dPort *firewall.Port) string {
-	switch {
-	case ipsetName == "":
+func transformIPsetName(ipsetName string, sPort, dPort *firewall.Port, action firewall.Action) string {
+	if ipsetName == "" {
 		return ""
+	}
+
+	// Include action in the ipset name to prevent squashing rules with different actions
+	actionSuffix := ""
+	if action == firewall.ActionDrop {
+		actionSuffix = "-drop"
+	}
+
+	switch {
 	case sPort != nil && dPort != nil:
-		return ipsetName + "-sport-dport"
+		return ipsetName + "-sport-dport" + actionSuffix
 	case sPort != nil:
-		return ipsetName + "-sport"
+		return ipsetName + "-sport" + actionSuffix
 	case dPort != nil:
-		return ipsetName + "-dport"
+		return ipsetName + "-dport" + actionSuffix
 	default:
-		return ipsetName
+		return ipsetName + actionSuffix
 	}
 }

client/firewall/iptables/manager_linux_test.go

@@ -3,6 +3,7 @@ package iptables
 import (
 	"fmt"
 	"net/netip"
+	"strings"
 	"testing"
 	"time"
 
@@ -15,7 +16,7 @@ import (
 
 var ifaceMock = &iFaceMock{
 	NameFunc: func() string {
-		return "lo"
+		return "wg-test"
 	},
 	AddressFunc: func() wgaddr.Address {
 		return wgaddr.Address{
@@ -109,10 +110,84 @@ func TestIptablesManager(t *testing.T) {
 	})
 }
 
+func TestIptablesManagerDenyRules(t *testing.T) {
+	ipv4Client, err := iptables.NewWithProtocol(iptables.ProtocolIPv4)
+	require.NoError(t, err)
+
+	manager, err := Create(ifaceMock)
+	require.NoError(t, err)
+	require.NoError(t, manager.Init(nil))
+
+	defer func() {
+		err := manager.Close(nil)
+		require.NoError(t, err)
+	}()
+
+	t.Run("add deny rule", func(t *testing.T) {
+		ip := netip.MustParseAddr("10.20.0.3")
+		port := &fw.Port{Values: []uint16{22}}
+
+		rule, err := manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", nil, port, fw.ActionDrop, "deny-ssh")
+		require.NoError(t, err, "failed to add deny rule")
+		require.NotEmpty(t, rule, "deny rule should not be empty")
+
+		// Verify the rule was added by checking iptables
+		for _, r := range rule {
+			rr := r.(*Rule)
+			checkRuleSpecs(t, ipv4Client, rr.chain, true, rr.specs...)
+		}
+	})
+
+	t.Run("deny rule precedence test", func(t *testing.T) {
+		ip := netip.MustParseAddr("10.20.0.4")
+		port := &fw.Port{Values: []uint16{80}}
+
+		// Add accept rule first
+		_, err := manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", nil, port, fw.ActionAccept, "accept-http")
+		require.NoError(t, err, "failed to add accept rule")
+
+		// Add deny rule second for same IP/port - this should take precedence
+		_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), "tcp", nil, port, fw.ActionDrop, "deny-http")
+		require.NoError(t, err, "failed to add deny rule")
+
+		// Inspect the actual iptables rules to verify deny rule comes before accept rule
+		rules, err := ipv4Client.List("filter", chainNameInputRules)
+		require.NoError(t, err, "failed to list iptables rules")
+
+		// Debug: print all rules
+		t.Logf("All iptables rules in chain %s:", chainNameInputRules)
+		for i, rule := range rules {
+			t.Logf("  [%d] %s", i, rule)
+		}
+
+		var denyRuleIndex, acceptRuleIndex int = -1, -1
+		for i, rule := range rules {
+			if strings.Contains(rule, "DROP") {
+				t.Logf("Found DROP rule at index %d: %s", i, rule)
+				if strings.Contains(rule, "deny-http") && strings.Contains(rule, "80") {
+					denyRuleIndex = i
+				}
+			}
+			if strings.Contains(rule, "ACCEPT") {
+				t.Logf("Found ACCEPT rule at index %d: %s", i, rule)
+				if strings.Contains(rule, "accept-http") && strings.Contains(rule, "80") {
+					acceptRuleIndex = i
+				}
+			}
+		}
+
+		require.NotEqual(t, -1, denyRuleIndex, "deny rule should exist in iptables")
+		require.NotEqual(t, -1, acceptRuleIndex, "accept rule should exist in iptables")
+		require.Less(t, denyRuleIndex, acceptRuleIndex,
+			"deny rule should come before accept rule in iptables chain (deny at index %d, accept at index %d)",
+			denyRuleIndex, acceptRuleIndex)
+	})
+}
+
 func TestIptablesManagerIPSet(t *testing.T) {
 	mock := &iFaceMock{
 		NameFunc: func() string {
-			return "lo"
+			return "wg-test"
 		},
 		AddressFunc: func() wgaddr.Address {
 			return wgaddr.Address{
@@ -176,7 +251,7 @@ func checkRuleSpecs(t *testing.T, ipv4Client *iptables.IPTables, chainName strin
 func TestIptablesCreatePerformance(t *testing.T) {
 	mock := &iFaceMock{
 		NameFunc: func() string {
-			return "lo"
+			return "wg-test"
 		},
 		AddressFunc: func() wgaddr.Address {
 			return wgaddr.Address{

client/firewall/nftables/acl_linux.go

@@ -341,30 +341,38 @@ func (m *AclManager) addIOFiltering(
 	userData := []byte(ruleId)
 
 	chain := m.chainInputRules
-	nftRule := m.rConn.AddRule(&nftables.Rule{
+	rule := &nftables.Rule{
 		Table:    m.workTable,
 		Chain:    chain,
 		Exprs:    mainExpressions,
 		UserData: userData,
-	})
+	}
+
+	// Insert DROP rules at the beginning, append ACCEPT rules at the end
+	var nftRule *nftables.Rule
+	if action == firewall.ActionDrop {
+		nftRule = m.rConn.InsertRule(rule)
+	} else {
+		nftRule = m.rConn.AddRule(rule)
+	}
 
 	if err := m.rConn.Flush(); err != nil {
 		return nil, fmt.Errorf(flushError, err)
 	}
 
-	rule := &Rule{
+	ruleStruct := &Rule{
 		nftRule:    nftRule,
 		mangleRule: m.createPreroutingRule(expressions, userData),
 		nftSet:     ipset,
 		ruleID:     ruleId,
 		ip:         ip,
 	}
-	m.rules[ruleId] = rule
+	m.rules[ruleId] = ruleStruct
 	if ipset != nil {
 		m.ipsetStore.AddReferenceToIpset(ipset.Name)
 	}
 
-	return rule, nil
+	return ruleStruct, nil
 }
 
 func (m *AclManager) createPreroutingRule(expressions []expr.Any, userData []byte) *nftables.Rule {

client/firewall/nftables/manager_linux_test.go

@@ -2,6 +2,7 @@ package nftables
 
 import (
 	"bytes"
+	"encoding/binary"
 	"fmt"
 	"net/netip"
 	"os/exec"
@@ -20,7 +21,7 @@ import (
 
 var ifaceMock = &iFaceMock{
 	NameFunc: func() string {
-		return "lo"
+		return "wg-test"
 	},
 	AddressFunc: func() wgaddr.Address {
 		return wgaddr.Address{
@@ -103,9 +104,8 @@ func TestNftablesManager(t *testing.T) {
 			Kind: expr.VerdictAccept,
 		},
 	}
-	compareExprsIgnoringCounters(t, rules[0].Exprs, expectedExprs1)
-
-	expectedExprs2 := []expr.Any{
+	// Since DROP rules are inserted at position 0, the DROP rule comes first
+	expectedDropExprs := []expr.Any{
 		&expr.Payload{
 			DestRegister: 1,
 			Base:         expr.PayloadBaseNetworkHeader,
@@ -141,7 +141,12 @@ func TestNftablesManager(t *testing.T) {
 		},
 		&expr.Verdict{Kind: expr.VerdictDrop},
 	}
-	require.ElementsMatch(t, rules[1].Exprs, expectedExprs2, "expected the same expressions")
+
+	// Compare DROP rule at position 0 (inserted first due to InsertRule)
+	compareExprsIgnoringCounters(t, rules[0].Exprs, expectedDropExprs)
+
+	// Compare connection tracking rule at position 1 (pushed down by DROP rule insertion)
+	compareExprsIgnoringCounters(t, rules[1].Exprs, expectedExprs1)
 
 	for _, r := range rule {
 		err = manager.DeletePeerRule(r)
@@ -160,10 +165,90 @@ func TestNftablesManager(t *testing.T) {
 	require.NoError(t, err, "failed to reset")
 }
 
+func TestNftablesManagerRuleOrder(t *testing.T) {
+	// This test verifies rule insertion order in nftables peer ACLs
+	// We add accept rule first, then deny rule to test ordering behavior
+	manager, err := Create(ifaceMock)
+	require.NoError(t, err)
+	require.NoError(t, manager.Init(nil))
+
+	defer func() {
+		err = manager.Close(nil)
+		require.NoError(t, err)
+	}()
+
+	ip := netip.MustParseAddr("100.96.0.2").Unmap()
+	testClient := &nftables.Conn{}
+
+	// Add accept rule first
+	_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionAccept, "accept-http")
+	require.NoError(t, err, "failed to add accept rule")
+
+	// Add deny rule second for the same traffic
+	_, err = manager.AddPeerFiltering(nil, ip.AsSlice(), fw.ProtocolTCP, nil, &fw.Port{Values: []uint16{80}}, fw.ActionDrop, "deny-http")
+	require.NoError(t, err, "failed to add deny rule")
+
+	err = manager.Flush()
+	require.NoError(t, err, "failed to flush")
+
+	rules, err := testClient.GetRules(manager.aclManager.workTable, manager.aclManager.chainInputRules)
+	require.NoError(t, err, "failed to get rules")
+
+	t.Logf("Found %d rules in nftables chain", len(rules))
+
+	// Find the accept and deny rules and verify deny comes before accept
+	var acceptRuleIndex, denyRuleIndex int = -1, -1
+	for i, rule := range rules {
+		hasAcceptHTTPSet := false
+		hasDenyHTTPSet := false
+		hasPort80 := false
+		var action string
+
+		for _, e := range rule.Exprs {
+			// Check for set lookup
+			if lookup, ok := e.(*expr.Lookup); ok {
+				if lookup.SetName == "accept-http" {
+					hasAcceptHTTPSet = true
+				} else if lookup.SetName == "deny-http" {
+					hasDenyHTTPSet = true
+				}
+			}
+			// Check for port 80
+			if cmp, ok := e.(*expr.Cmp); ok {
+				if cmp.Op == expr.CmpOpEq && len(cmp.Data) == 2 && binary.BigEndian.Uint16(cmp.Data) == 80 {
+					hasPort80 = true
+				}
+			}
+			// Check for verdict
+			if verdict, ok := e.(*expr.Verdict); ok {
+				if verdict.Kind == expr.VerdictAccept {
+					action = "ACCEPT"
+				} else if verdict.Kind == expr.VerdictDrop {
+					action = "DROP"
+				}
+			}
+		}
+
+		if hasAcceptHTTPSet && hasPort80 && action == "ACCEPT" {
+			t.Logf("Rule [%d]: accept-http set + Port 80 + ACCEPT", i)
+			acceptRuleIndex = i
+		} else if hasDenyHTTPSet && hasPort80 && action == "DROP" {
+			t.Logf("Rule [%d]: deny-http set + Port 80 + DROP", i)
+			denyRuleIndex = i
+		}
+	}
+
+	require.NotEqual(t, -1, acceptRuleIndex, "accept rule should exist in nftables")
+	require.NotEqual(t, -1, denyRuleIndex, "deny rule should exist in nftables")
+	require.Less(t, denyRuleIndex, acceptRuleIndex,
+		"deny rule should come before accept rule in nftables chain (deny at index %d, accept at index %d)",
+		denyRuleIndex, acceptRuleIndex)
+}
+
 func TestNFtablesCreatePerformance(t *testing.T) {
 	mock := &iFaceMock{
 		NameFunc: func() string {
-			return "lo"
+			return "wg-test"
 		},
 		AddressFunc: func() wgaddr.Address {
 			return wgaddr.Address{

client/firewall/uspfilter/allow_netbird.go

@@ -18,6 +18,7 @@ func (m *Manager) Close(stateManager *statemanager.Manager) error {
 	defer m.mutex.Unlock()
 
 	m.outgoingRules = make(map[netip.Addr]RuleSet)
+	m.incomingDenyRules = make(map[netip.Addr]RuleSet)
 	m.incomingRules = make(map[netip.Addr]RuleSet)
 
 	if m.udpTracker != nil {

client/firewall/uspfilter/allow_netbird_windows.go

@@ -27,6 +27,7 @@ func (m *Manager) Close(*statemanager.Manager) error {
 	defer m.mutex.Unlock()
 
 	m.outgoingRules = make(map[netip.Addr]RuleSet)
+	m.incomingDenyRules = make(map[netip.Addr]RuleSet)
 	m.incomingRules = make(map[netip.Addr]RuleSet)
 
 	if m.udpTracker != nil {

client/firewall/uspfilter/filter.go

@@ -70,14 +70,13 @@ func (r RouteRules) Sort() {
 
 // Manager userspace firewall manager
 type Manager struct {
-	// outgoingRules is used for hooks only
-	outgoingRules map[netip.Addr]RuleSet
-	// incomingRules is used for filtering and hooks
-	incomingRules  map[netip.Addr]RuleSet
-	routeRules     RouteRules
-	decoders       sync.Pool
-	wgIface        common.IFaceMapper
-	nativeFirewall firewall.Manager
+	outgoingRules     map[netip.Addr]RuleSet
+	incomingDenyRules map[netip.Addr]RuleSet
+	incomingRules     map[netip.Addr]RuleSet
+	routeRules        RouteRules
+	decoders          sync.Pool
+	wgIface           common.IFaceMapper
+	nativeFirewall    firewall.Manager
 
 	mutex sync.RWMutex
 
@@ -186,6 +185,7 @@ func create(iface common.IFaceMapper, nativeFirewall firewall.Manager, disableSe
 		},
 		nativeFirewall:      nativeFirewall,
 		outgoingRules:       make(map[netip.Addr]RuleSet),
+		incomingDenyRules:   make(map[netip.Addr]RuleSet),
 		incomingRules:       make(map[netip.Addr]RuleSet),
 		wgIface:             iface,
 		localipmanager:      newLocalIPManager(),
@@ -417,10 +417,17 @@ func (m *Manager) AddPeerFiltering(
 	}
 
 	m.mutex.Lock()
-	if _, ok := m.incomingRules[r.ip]; !ok {
-		m.incomingRules[r.ip] = make(RuleSet)
+	var targetMap map[netip.Addr]RuleSet
+	if r.drop {
+		targetMap = m.incomingDenyRules
+	} else {
+		targetMap = m.incomingRules
 	}
-	m.incomingRules[r.ip][r.id] = r
+
+	if _, ok := targetMap[r.ip]; !ok {
+		targetMap[r.ip] = make(RuleSet)
+	}
+	targetMap[r.ip][r.id] = r
 	m.mutex.Unlock()
 	return []firewall.Rule{&r}, nil
 }
@@ -507,10 +514,24 @@ func (m *Manager) DeletePeerRule(rule firewall.Rule) error {
 		return fmt.Errorf("delete rule: invalid rule type: %T", rule)
 	}
 
-	if _, ok := m.incomingRules[r.ip][r.id]; !ok {
+	var sourceMap map[netip.Addr]RuleSet
+	if r.drop {
+		sourceMap = m.incomingDenyRules
+	} else {
+		sourceMap = m.incomingRules
+	}
+
+	if ruleset, ok := sourceMap[r.ip]; ok {
+		if _, exists := ruleset[r.id]; !exists {
+			return fmt.Errorf("delete rule: no rule with such id: %v", r.id)
+		}
+		delete(ruleset, r.id)
+		if len(ruleset) == 0 {
+			delete(sourceMap, r.ip)
+		}
+	} else {
 		return fmt.Errorf("delete rule: no rule with such id: %v", r.id)
 	}
-	delete(m.incomingRules[r.ip], r.id)
 
 	return nil
 }
@@ -572,7 +593,7 @@ func (m *Manager) UpdateSet(set firewall.Set, prefixes []netip.Prefix) error {
 	return nil
 }
 
-// FilterOutBound filters outgoing packets
+// FilterOutbound filters outgoing packets
 func (m *Manager) FilterOutbound(packetData []byte, size int) bool {
 	return m.filterOutbound(packetData, size)
 }
@@ -761,7 +782,7 @@ func (m *Manager) filterInbound(packetData []byte, size int) bool {
 // handleLocalTraffic handles local traffic.
 // If it returns true, the packet should be dropped.
 func (m *Manager) handleLocalTraffic(d *decoder, srcIP, dstIP netip.Addr, packetData []byte, size int) bool {
-	ruleID, blocked := m.peerACLsBlock(srcIP, packetData, m.incomingRules, d)
+	ruleID, blocked := m.peerACLsBlock(srcIP, d, packetData)
 	if blocked {
 		_, pnum := getProtocolFromPacket(d)
 		srcPort, dstPort := getPortsFromPacket(d)
@@ -971,26 +992,28 @@ func (m *Manager) isSpecialICMP(d *decoder) bool {
 		icmpType == layers.ICMPv4TypeTimeExceeded
 }
 
-func (m *Manager) peerACLsBlock(srcIP netip.Addr, packetData []byte, rules map[netip.Addr]RuleSet, d *decoder) ([]byte, bool) {
+func (m *Manager) peerACLsBlock(srcIP netip.Addr, d *decoder, packetData []byte) ([]byte, bool) {
 	m.mutex.RLock()
 	defer m.mutex.RUnlock()
+
 	if m.isSpecialICMP(d) {
 		return nil, false
 	}
 
-	if mgmtId, filter, ok := validateRule(srcIP, packetData, rules[srcIP], d); ok {
+	if mgmtId, filter, ok := validateRule(srcIP, packetData, m.incomingDenyRules[srcIP], d); ok {
 		return mgmtId, filter
 	}
 
-	if mgmtId, filter, ok := validateRule(srcIP, packetData, rules[netip.IPv4Unspecified()], d); ok {
+	if mgmtId, filter, ok := validateRule(srcIP, packetData, m.incomingRules[srcIP], d); ok {
+		return mgmtId, filter
+	}
+	if mgmtId, filter, ok := validateRule(srcIP, packetData, m.incomingRules[netip.IPv4Unspecified()], d); ok {
+		return mgmtId, filter
+	}
+	if mgmtId, filter, ok := validateRule(srcIP, packetData, m.incomingRules[netip.IPv6Unspecified()], d); ok {
 		return mgmtId, filter
 	}
 
-	if mgmtId, filter, ok := validateRule(srcIP, packetData, rules[netip.IPv6Unspecified()], d); ok {
-		return mgmtId, filter
-	}
-
-	// Default policy: DROP ALL
 	return nil, true
 }
 
@@ -1013,6 +1036,7 @@ func portsMatch(rulePort *firewall.Port, packetPort uint16) bool {
 
 func validateRule(ip netip.Addr, packetData []byte, rules map[string]PeerRule, d *decoder) ([]byte, bool, bool) {
 	payloadLayer := d.decoded[1]
+
 	for _, rule := range rules {
 		if rule.matchByIP && ip.Compare(rule.ip) != 0 {
 			continue
@@ -1045,6 +1069,7 @@ func validateRule(ip netip.Addr, packetData []byte, rules map[string]PeerRule, d
 			return rule.mgmtId, rule.drop, true
 		}
 	}
+
 	return nil, false, false
 }
 
@@ -1116,6 +1141,7 @@ func (m *Manager) AddUDPPacketHook(in bool, ip netip.Addr, dPort uint16, hook fu
 
 	m.mutex.Lock()
 	if in {
+		// Incoming UDP hooks are stored in allow rules map
 		if _, ok := m.incomingRules[r.ip]; !ok {
 			m.incomingRules[r.ip] = make(map[string]PeerRule)
 		}
@@ -1136,6 +1162,7 @@ func (m *Manager) RemovePacketHook(hookID string) error {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 
+	// Check incoming hooks (stored in allow rules)
 	for _, arr := range m.incomingRules {
 		for _, r := range arr {
 			if r.id == hookID {
@@ -1144,6 +1171,7 @@ func (m *Manager) RemovePacketHook(hookID string) error {
 			}
 		}
 	}
+	// Check outgoing hooks
 	for _, arr := range m.outgoingRules {
 		for _, r := range arr {
 			if r.id == hookID {

client/firewall/uspfilter/filter_filter_test.go

@@ -458,6 +458,31 @@ func TestPeerACLFiltering(t *testing.T) {
 			ruleAction:      fw.ActionDrop,
 			shouldBeBlocked: true,
 		},
+		{
+			name:            "Peer ACL - Drop rule should override accept all rule",
+			srcIP:           "100.10.0.1",
+			dstIP:           "100.10.0.100",
+			proto:           fw.ProtocolTCP,
+			srcPort:         12345,
+			dstPort:         22,
+			ruleIP:          "100.10.0.1",
+			ruleProto:       fw.ProtocolTCP,
+			ruleDstPort:     &fw.Port{Values: []uint16{22}},
+			ruleAction:      fw.ActionDrop,
+			shouldBeBlocked: true,
+		},
+		{
+			name:            "Peer ACL - Drop all traffic from specific IP",
+			srcIP:           "100.10.0.99",
+			dstIP:           "100.10.0.100",
+			proto:           fw.ProtocolTCP,
+			srcPort:         12345,
+			dstPort:         80,
+			ruleIP:          "100.10.0.99",
+			ruleProto:       fw.ProtocolALL,
+			ruleAction:      fw.ActionDrop,
+			shouldBeBlocked: true,
+		},
 	}
 
 	t.Run("Implicit DROP (no rules)", func(t *testing.T) {
@@ -468,13 +493,11 @@ func TestPeerACLFiltering(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-
 			if tc.ruleAction == fw.ActionDrop {
-				// add general accept rule to test drop rule
-				// TODO: this only works because 0.0.0.0 is tested last, we need to implement order
+				// add general accept rule for the same IP to test drop rule precedence
 				rules, err := manager.AddPeerFiltering(
 					nil,
-					net.ParseIP("0.0.0.0"),
+					net.ParseIP(tc.ruleIP),
 					fw.ProtocolALL,
 					nil,
 					nil,

client/firewall/uspfilter/filter_test.go

@@ -136,9 +136,22 @@ func TestManagerDeleteRule(t *testing.T) {
 		return
 	}
 
+	// Check rules exist in appropriate maps
 	for _, r := range rule2 {
-		if _, ok := m.incomingRules[ip][r.ID()]; !ok {
-			t.Errorf("rule2 is not in the incomingRules")
+		peerRule, ok := r.(*PeerRule)
+		if !ok {
+			t.Errorf("rule should be a PeerRule")
+			continue
+		}
+		// Check if rule exists in deny or allow maps based on action
+		var found bool
+		if peerRule.drop {
+			_, found = m.incomingDenyRules[ip][r.ID()]
+		} else {
+			_, found = m.incomingRules[ip][r.ID()]
+		}
+		if !found {
+			t.Errorf("rule2 is not in the expected rules map")
 		}
 	}
 
@@ -150,9 +163,22 @@ func TestManagerDeleteRule(t *testing.T) {
 		}
 	}
 
+	// Check rules are removed from appropriate maps
 	for _, r := range rule2 {
-		if _, ok := m.incomingRules[ip][r.ID()]; ok {
-			t.Errorf("rule2 is not in the incomingRules")
+		peerRule, ok := r.(*PeerRule)
+		if !ok {
+			t.Errorf("rule should be a PeerRule")
+			continue
+		}
+		// Check if rule is removed from deny or allow maps based on action
+		var found bool
+		if peerRule.drop {
+			_, found = m.incomingDenyRules[ip][r.ID()]
+		} else {
+			_, found = m.incomingRules[ip][r.ID()]
+		}
+		if found {
+			t.Errorf("rule2 should be removed from the rules map")
 		}
 	}
 }
@@ -196,16 +222,17 @@ func TestAddUDPPacketHook(t *testing.T) {
 
 			var addedRule PeerRule
 			if tt.in {
+				// Incoming UDP hooks are stored in allow rules map
 				if len(manager.incomingRules[tt.ip]) != 1 {
-					t.Errorf("expected 1 incoming rule, got %d", len(manager.incomingRules))
+					t.Errorf("expected 1 incoming rule, got %d", len(manager.incomingRules[tt.ip]))
 					return
 				}
 				for _, rule := range manager.incomingRules[tt.ip] {
 					addedRule = rule
 				}
 			} else {
-				if len(manager.outgoingRules) != 1 {
-					t.Errorf("expected 1 outgoing rule, got %d", len(manager.outgoingRules))
+				if len(manager.outgoingRules[tt.ip]) != 1 {
+					t.Errorf("expected 1 outgoing rule, got %d", len(manager.outgoingRules[tt.ip]))
 					return
 				}
 				for _, rule := range manager.outgoingRules[tt.ip] {
@@ -261,8 +288,8 @@ func TestManagerReset(t *testing.T) {
 		return
 	}
 
-	if len(m.outgoingRules) != 0 || len(m.incomingRules) != 0 {
-		t.Errorf("rules is not empty")
+	if len(m.outgoingRules) != 0 || len(m.incomingRules) != 0 || len(m.incomingDenyRules) != 0 {
+		t.Errorf("rules are not empty")
 	}
 }
 

client/firewall/uspfilter/tracer.go

@@ -314,7 +314,7 @@ func (m *Manager) buildConntrackStateMessage(d *decoder) string {
 func (m *Manager) handleLocalDelivery(trace *PacketTrace, packetData []byte, d *decoder, srcIP, dstIP netip.Addr) bool {
 	trace.AddResult(StageRouting, "Packet destined for local delivery", true)
 
-	ruleId, blocked := m.peerACLsBlock(srcIP, packetData, m.incomingRules, d)
+	ruleId, blocked := m.peerACLsBlock(srcIP, d, packetData)
 
 	strRuleId := "<no id>"
 	if ruleId != nil {

client/iface/bind/ice_bind.go

@@ -8,7 +8,7 @@ import (
 	"runtime"
 	"sync"
 
-	"github.com/pion/stun/v2"
+	"github.com/pion/stun/v3"
 	"github.com/pion/transport/v3"
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/net/ipv4"
@@ -56,10 +56,11 @@ type ICEBind struct {
 	muUDPMux         sync.Mutex
 	udpMux           *UniversalUDPMuxDefault
 	address          wgaddr.Address
+	mtu              uint16
 	activityRecorder *ActivityRecorder
 }
 
-func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Address) *ICEBind {
+func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Address, mtu uint16) *ICEBind {
 	b, _ := wgConn.NewStdNetBind().(*wgConn.StdNetBind)
 	ib := &ICEBind{
 		StdNetBind:       b,
@@ -69,6 +70,7 @@ func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Ad
 		endpoints:        make(map[netip.Addr]net.Conn),
 		closedChan:       make(chan struct{}),
 		closed:           true,
+		mtu:              mtu,
 		address:          address,
 		activityRecorder: NewActivityRecorder(),
 	}
@@ -80,6 +82,10 @@ func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Ad
 	return ib
 }
 
+func (s *ICEBind) MTU() uint16 {
+	return s.mtu
+}
+
 func (s *ICEBind) Open(uport uint16) ([]wgConn.ReceiveFunc, uint16, error) {
 	s.closed = false
 	s.closedChanMu.Lock()
@@ -158,6 +164,7 @@ func (s *ICEBind) createIPv4ReceiverFn(pc *ipv4.PacketConn, conn *net.UDPConn, r
 			Net:       s.transportNet,
 			FilterFn:  s.filterFn,
 			WGAddress: s.address,
+			MTU:       s.mtu,
 		},
 	)
 	return func(bufs [][]byte, sizes []int, eps []wgConn.Endpoint) (n int, err error) {

client/iface/bind/udp_mux.go

@@ -8,9 +8,9 @@ import (
 	"strings"
 	"sync"
 
-	"github.com/pion/ice/v3"
+	"github.com/pion/ice/v4"
 	"github.com/pion/logging"
-	"github.com/pion/stun/v2"
+	"github.com/pion/stun/v3"
 	"github.com/pion/transport/v3"
 	"github.com/pion/transport/v3/stdnet"
 	log "github.com/sirupsen/logrus"

client/iface/bind/udp_mux_ios.go

@@ -4,4 +4,4 @@ package bind
 
 func (m *UDPMuxDefault) notifyAddressRemoval(addr string) {
 	// iOS doesn't support nbnet hooks, so this is a no-op
-}
+}

client/iface/bind/udp_mux_universal.go

@@ -15,9 +15,10 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	"github.com/pion/logging"
-	"github.com/pion/stun/v2"
+	"github.com/pion/stun/v3"
 	"github.com/pion/transport/v3"
 
+	"github.com/netbirdio/netbird/client/iface/bufsize"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 )
 
@@ -44,6 +45,7 @@ type UniversalUDPMuxParams struct {
 	Net                   transport.Net
 	FilterFn              FilterFn
 	WGAddress             wgaddr.Address
+	MTU                   uint16
 }
 
 // NewUniversalUDPMuxDefault creates an implementation of UniversalUDPMux embedding UDPMux
@@ -84,7 +86,7 @@ func NewUniversalUDPMuxDefault(params UniversalUDPMuxParams) *UniversalUDPMuxDef
 // just ignore other packets printing an warning message.
 // It is a blocking method, consider running in a go routine.
 func (m *UniversalUDPMuxDefault) ReadFromConn(ctx context.Context) {
-	buf := make([]byte, 1500)
+	buf := make([]byte, m.params.MTU+bufsize.WGBufferOverhead)
 	for {
 		select {
 		case <-ctx.Done():

client/iface/bufsize/bufsize.go

@@ -0,0 +1,9 @@
+package bufsize
+
+const (
+	// WGBufferOverhead represents the additional buffer space needed beyond MTU
+	// for WireGuard packet encapsulation (WG header + UDP + IP + safety margin)
+	// Original hardcoded buffers were 1500, default MTU is 1280, so overhead = 220
+	// TODO: Calculate this properly based on actual protocol overhead instead of using hardcoded difference
+	WGBufferOverhead = 220
+)

client/iface/device.go

@@ -17,6 +17,7 @@ type WGTunDevice interface {
 	Up() (*bind.UniversalUDPMuxDefault, error)
 	UpdateAddr(address wgaddr.Address) error
 	WgAddress() wgaddr.Address
+	MTU() uint16
 	DeviceName() string
 	Close() error
 	FilteredDevice() *device.FilteredDevice

client/iface/device/device_android.go

@@ -21,7 +21,7 @@ type WGTunDevice struct {
 	address    wgaddr.Address
 	port       int
 	key        string
-	mtu        int
+	mtu        uint16
 	iceBind    *bind.ICEBind
 	tunAdapter TunAdapter
 	disableDNS bool
@@ -33,7 +33,7 @@ type WGTunDevice struct {
 	configurer     WGConfigurer
 }
 
-func NewTunDevice(address wgaddr.Address, port int, key string, mtu int, iceBind *bind.ICEBind, tunAdapter TunAdapter, disableDNS bool) *WGTunDevice {
+func NewTunDevice(address wgaddr.Address, port int, key string, mtu uint16, iceBind *bind.ICEBind, tunAdapter TunAdapter, disableDNS bool) *WGTunDevice {
 	return &WGTunDevice{
 		address:    address,
 		port:       port,
@@ -58,7 +58,7 @@ func (t *WGTunDevice) Create(routes []string, dns string, searchDomains []string
 		searchDomainsToString = ""
 	}
 
-	fd, err := t.tunAdapter.ConfigureInterface(t.address.String(), t.mtu, dns, searchDomainsToString, routesString)
+	fd, err := t.tunAdapter.ConfigureInterface(t.address.String(), int(t.mtu), dns, searchDomainsToString, routesString)
 	if err != nil {
 		log.Errorf("failed to create Android interface: %s", err)
 		return nil, err
@@ -137,6 +137,10 @@ func (t *WGTunDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *WGTunDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *WGTunDevice) FilteredDevice() *FilteredDevice {
 	return t.filteredDevice
 }

client/iface/device/device_darwin.go

@@ -21,7 +21,7 @@ type TunDevice struct {
 	address wgaddr.Address
 	port    int
 	key     string
-	mtu     int
+	mtu     uint16
 	iceBind *bind.ICEBind
 
 	device         *device.Device
@@ -30,7 +30,7 @@ type TunDevice struct {
 	configurer     WGConfigurer
 }
 
-func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu int, iceBind *bind.ICEBind) *TunDevice {
+func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu uint16, iceBind *bind.ICEBind) *TunDevice {
 	return &TunDevice{
 		name:    name,
 		address: address,
@@ -42,7 +42,7 @@ func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu
 }
 
 func (t *TunDevice) Create() (WGConfigurer, error) {
-	tunDevice, err := tun.CreateTUN(t.name, t.mtu)
+	tunDevice, err := tun.CreateTUN(t.name, int(t.mtu))
 	if err != nil {
 		return nil, fmt.Errorf("error creating tun device: %s", err)
 	}
@@ -111,6 +111,10 @@ func (t *TunDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *TunDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *TunDevice) DeviceName() string {
 	return t.name
 }

client/iface/device/device_ios.go

@@ -22,6 +22,7 @@ type TunDevice struct {
 	address wgaddr.Address
 	port    int
 	key     string
+	mtu     uint16
 	iceBind *bind.ICEBind
 	tunFd   int
 
@@ -31,12 +32,13 @@ type TunDevice struct {
 	configurer     WGConfigurer
 }
 
-func NewTunDevice(name string, address wgaddr.Address, port int, key string, iceBind *bind.ICEBind, tunFd int) *TunDevice {
+func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu uint16, iceBind *bind.ICEBind, tunFd int) *TunDevice {
 	return &TunDevice{
 		name:    name,
 		address: address,
 		port:    port,
 		key:     key,
+		mtu:     mtu,
 		iceBind: iceBind,
 		tunFd:   tunFd,
 	}
@@ -125,6 +127,10 @@ func (t *TunDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *TunDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *TunDevice) UpdateAddr(_ wgaddr.Address) error {
 	// todo implement
 	return nil

client/iface/device/device_kernel_unix.go

@@ -24,7 +24,7 @@ type TunKernelDevice struct {
 	address      wgaddr.Address
 	wgPort       int
 	key          string
-	mtu          int
+	mtu          uint16
 	ctx          context.Context
 	ctxCancel    context.CancelFunc
 	transportNet transport.Net
@@ -36,7 +36,7 @@ type TunKernelDevice struct {
 	filterFn bind.FilterFn
 }
 
-func NewKernelDevice(name string, address wgaddr.Address, wgPort int, key string, mtu int, transportNet transport.Net) *TunKernelDevice {
+func NewKernelDevice(name string, address wgaddr.Address, wgPort int, key string, mtu uint16, transportNet transport.Net) *TunKernelDevice {
 	ctx, cancel := context.WithCancel(context.Background())
 	return &TunKernelDevice{
 		ctx:          ctx,
@@ -66,7 +66,7 @@ func (t *TunKernelDevice) Create() (WGConfigurer, error) {
 	// TODO: do a MTU discovery
 	log.Debugf("setting MTU: %d interface: %s", t.mtu, t.name)
 
-	if err := link.setMTU(t.mtu); err != nil {
+	if err := link.setMTU(int(t.mtu)); err != nil {
 		return nil, fmt.Errorf("set mtu: %w", err)
 	}
 
@@ -96,7 +96,7 @@ func (t *TunKernelDevice) Up() (*bind.UniversalUDPMuxDefault, error) {
 		return nil, err
 	}
 
-	rawSock, err := sharedsock.Listen(t.wgPort, sharedsock.NewIncomingSTUNFilter())
+	rawSock, err := sharedsock.Listen(t.wgPort, sharedsock.NewIncomingSTUNFilter(), t.mtu)
 	if err != nil {
 		return nil, err
 	}
@@ -111,6 +111,7 @@ func (t *TunKernelDevice) Up() (*bind.UniversalUDPMuxDefault, error) {
 		Net:       t.transportNet,
 		FilterFn:  t.filterFn,
 		WGAddress: t.address,
+		MTU:       t.mtu,
 	}
 	mux := bind.NewUniversalUDPMuxDefault(bindParams)
 	go mux.ReadFromConn(t.ctx)
@@ -158,6 +159,10 @@ func (t *TunKernelDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *TunKernelDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *TunKernelDevice) DeviceName() string {
 	return t.name
 }

client/iface/device/device_netstack.go

@@ -1,6 +1,3 @@
-//go:build !android
-// +build !android
-
 package device
 
 import (
@@ -22,7 +19,7 @@ type TunNetstackDevice struct {
 	address       wgaddr.Address
 	port          int
 	key           string
-	mtu           int
+	mtu           uint16
 	listenAddress string
 	iceBind       *bind.ICEBind
 
@@ -35,7 +32,7 @@ type TunNetstackDevice struct {
 	net *netstack.Net
 }
 
-func NewNetstackDevice(name string, address wgaddr.Address, wgPort int, key string, mtu int, iceBind *bind.ICEBind, listenAddress string) *TunNetstackDevice {
+func NewNetstackDevice(name string, address wgaddr.Address, wgPort int, key string, mtu uint16, iceBind *bind.ICEBind, listenAddress string) *TunNetstackDevice {
 	return &TunNetstackDevice{
 		name:          name,
 		address:       address,
@@ -47,7 +44,7 @@ func NewNetstackDevice(name string, address wgaddr.Address, wgPort int, key stri
 	}
 }
 
-func (t *TunNetstackDevice) Create() (WGConfigurer, error) {
+func (t *TunNetstackDevice) create() (WGConfigurer, error) {
 	log.Info("create nbnetstack tun interface")
 
 	// TODO: get from service listener runtime IP
@@ -57,7 +54,7 @@ func (t *TunNetstackDevice) Create() (WGConfigurer, error) {
 	}
 
 	log.Debugf("netstack using address: %s", t.address.IP)
-	t.nsTun = nbnetstack.NewNetStackTun(t.listenAddress, t.address.IP, dnsAddr, t.mtu)
+	t.nsTun = nbnetstack.NewNetStackTun(t.listenAddress, t.address.IP, dnsAddr, int(t.mtu))
 	log.Debugf("netstack using dns address: %s", dnsAddr)
 	tunIface, net, err := t.nsTun.Create()
 	if err != nil {
@@ -125,6 +122,10 @@ func (t *TunNetstackDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *TunNetstackDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *TunNetstackDevice) DeviceName() string {
 	return t.name
 }

client/iface/device/device_netstack_android.go

@@ -0,0 +1,7 @@
+//go:build android
+
+package device
+
+func (t *TunNetstackDevice) Create(routes []string, dns string, searchDomains []string) (WGConfigurer, error) {
+	return t.create()
+}

client/iface/device/device_netstack_generic.go

@@ -0,0 +1,7 @@
+//go:build !android
+
+package device
+
+func (t *TunNetstackDevice) Create() (WGConfigurer, error) {
+	return t.create()
+}

client/iface/device/device_usp_unix.go

@@ -20,7 +20,7 @@ type USPDevice struct {
 	address wgaddr.Address
 	port    int
 	key     string
-	mtu     int
+	mtu     uint16
 	iceBind *bind.ICEBind
 
 	device         *device.Device
@@ -29,7 +29,7 @@ type USPDevice struct {
 	configurer     WGConfigurer
 }
 
-func NewUSPDevice(name string, address wgaddr.Address, port int, key string, mtu int, iceBind *bind.ICEBind) *USPDevice {
+func NewUSPDevice(name string, address wgaddr.Address, port int, key string, mtu uint16, iceBind *bind.ICEBind) *USPDevice {
 	log.Infof("using userspace bind mode")
 
 	return &USPDevice{
@@ -44,9 +44,9 @@ func NewUSPDevice(name string, address wgaddr.Address, port int, key string, mtu
 
 func (t *USPDevice) Create() (WGConfigurer, error) {
 	log.Info("create tun interface")
-	tunIface, err := tun.CreateTUN(t.name, t.mtu)
+	tunIface, err := tun.CreateTUN(t.name, int(t.mtu))
 	if err != nil {
-		log.Debugf("failed to create tun interface (%s, %d): %s", t.name, t.mtu, err)
+		log.Debugf("failed to create tun interface (%s, %d): %s", t.name, int(t.mtu), err)
 		return nil, fmt.Errorf("error creating tun device: %s", err)
 	}
 	t.filteredDevice = newDeviceFilter(tunIface)
@@ -118,6 +118,10 @@ func (t *USPDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *USPDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *USPDevice) DeviceName() string {
 	return t.name
 }

client/iface/device/device_windows.go

@@ -23,7 +23,7 @@ type TunDevice struct {
 	address wgaddr.Address
 	port    int
 	key     string
-	mtu     int
+	mtu     uint16
 	iceBind *bind.ICEBind
 
 	device          *device.Device
@@ -33,7 +33,7 @@ type TunDevice struct {
 	configurer      WGConfigurer
 }
 
-func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu int, iceBind *bind.ICEBind) *TunDevice {
+func NewTunDevice(name string, address wgaddr.Address, port int, key string, mtu uint16, iceBind *bind.ICEBind) *TunDevice {
 	return &TunDevice{
 		name:    name,
 		address: address,
@@ -59,7 +59,7 @@ func (t *TunDevice) Create() (WGConfigurer, error) {
 		return nil, err
 	}
 	log.Info("create tun interface")
-	tunDevice, err := tun.CreateTUNWithRequestedGUID(t.name, &guid, t.mtu)
+	tunDevice, err := tun.CreateTUNWithRequestedGUID(t.name, &guid, int(t.mtu))
 	if err != nil {
 		return nil, fmt.Errorf("error creating tun device: %s", err)
 	}
@@ -144,6 +144,10 @@ func (t *TunDevice) WgAddress() wgaddr.Address {
 	return t.address
 }
 
+func (t *TunDevice) MTU() uint16 {
+	return t.mtu
+}
+
 func (t *TunDevice) DeviceName() string {
 	return t.name
 }

client/iface/device_android.go

@@ -15,6 +15,7 @@ type WGTunDevice interface {
 	Up() (*bind.UniversalUDPMuxDefault, error)
 	UpdateAddr(address wgaddr.Address) error
 	WgAddress() wgaddr.Address
+	MTU() uint16
 	DeviceName() string
 	Close() error
 	FilteredDevice() *device.FilteredDevice

client/iface/iface.go

@@ -26,6 +26,8 @@ import (
 
 const (
 	DefaultMTU         = 1280
+	MinMTU             = 576
+	MaxMTU             = 8192
 	DefaultWgPort      = 51820
 	WgInterfaceDefault = configurer.WgInterfaceDefault
 )
@@ -35,6 +37,17 @@ var (
 	ErrIfaceNotFound = fmt.Errorf("wireguard interface not found")
 )
 
+// ValidateMTU validates that MTU is within acceptable range
+func ValidateMTU(mtu uint16) error {
+	if mtu < MinMTU {
+		return fmt.Errorf("MTU %d below minimum (%d bytes)", mtu, MinMTU)
+	}
+	if mtu > MaxMTU {
+		return fmt.Errorf("MTU %d exceeds maximum supported size (%d bytes)", mtu, MaxMTU)
+	}
+	return nil
+}
+
 type wgProxyFactory interface {
 	GetProxy() wgproxy.Proxy
 	Free() error
@@ -45,7 +58,7 @@ type WGIFaceOpts struct {
 	Address      string
 	WGPort       int
 	WGPrivKey    string
-	MTU          int
+	MTU          uint16
 	MobileArgs   *device.MobileIFaceArguments
 	TransportNet transport.Net
 	FilterFn     bind.FilterFn
@@ -82,6 +95,10 @@ func (w *WGIface) Address() wgaddr.Address {
 	return w.tun.WgAddress()
 }
 
+func (w *WGIface) MTU() uint16 {
+	return w.tun.MTU()
+}
+
 // ToInterface returns the net.Interface for the Wireguard interface
 func (r *WGIface) ToInterface() *net.Interface {
 	name := r.tun.DeviceName()

client/iface/iface_new_android.go

@@ -3,6 +3,7 @@ package iface
 import (
 	"github.com/netbirdio/netbird/client/iface/bind"
 	"github.com/netbirdio/netbird/client/iface/device"
+	"github.com/netbirdio/netbird/client/iface/netstack"
 	"github.com/netbirdio/netbird/client/iface/wgaddr"
 	"github.com/netbirdio/netbird/client/iface/wgproxy"
 )
@@ -14,7 +15,16 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 		return nil, err
 	}
 
-	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress)
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
+
+	if netstack.IsEnabled() {
+		wgIFace := &WGIface{
+			userspaceBind:  true,
+			tun:            device.NewNetstackDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr()),
+			wgProxyFactory: wgproxy.NewUSPFactory(iceBind),
+		}
+		return wgIFace, nil
+	}
 
 	wgIFace := &WGIface{
 		userspaceBind:  true,

client/iface/iface_new_darwin.go

@@ -17,7 +17,7 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 		return nil, err
 	}
 
-	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress)
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 
 	var tun WGTunDevice
 	if netstack.IsEnabled() {

client/iface/iface_new_ios.go

@@ -16,10 +16,10 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 		return nil, err
 	}
 
-	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress)
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 
 	wgIFace := &WGIface{
-		tun:            device.NewTunDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, iceBind, opts.MobileArgs.TunFd),
+		tun:            device.NewTunDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, opts.MobileArgs.TunFd),
 		userspaceBind:  true,
 		wgProxyFactory: wgproxy.NewUSPFactory(iceBind),
 	}

client/iface/iface_new_unix.go

@@ -22,7 +22,7 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 	wgIFace := &WGIface{}
 
 	if netstack.IsEnabled() {
-		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress)
+		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 		wgIFace.tun = device.NewNetstackDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind, netstack.ListenAddr())
 		wgIFace.userspaceBind = true
 		wgIFace.wgProxyFactory = wgproxy.NewUSPFactory(iceBind)
@@ -31,11 +31,11 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 
 	if device.WireGuardModuleIsLoaded() {
 		wgIFace.tun = device.NewKernelDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, opts.TransportNet)
-		wgIFace.wgProxyFactory = wgproxy.NewKernelFactory(opts.WGPort)
+		wgIFace.wgProxyFactory = wgproxy.NewKernelFactory(opts.WGPort, opts.MTU)
 		return wgIFace, nil
 	}
 	if device.ModuleTunIsLoaded() {
-		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress)
+		iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 		wgIFace.tun = device.NewUSPDevice(opts.IFaceName, wgAddress, opts.WGPort, opts.WGPrivKey, opts.MTU, iceBind)
 		wgIFace.userspaceBind = true
 		wgIFace.wgProxyFactory = wgproxy.NewUSPFactory(iceBind)

client/iface/iface_new_windows.go

@@ -14,7 +14,7 @@ func NewWGIFace(opts WGIFaceOpts) (*WGIface, error) {
 	if err != nil {
 		return nil, err
 	}
-	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress)
+	iceBind := bind.NewICEBind(opts.TransportNet, opts.FilterFn, wgAddress, opts.MTU)
 
 	var tun WGTunDevice
 	if netstack.IsEnabled() {

client/iface/wgproxy/bind/proxy.go

@@ -12,6 +12,7 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	"github.com/netbirdio/netbird/client/iface/bind"
+	"github.com/netbirdio/netbird/client/iface/bufsize"
 	"github.com/netbirdio/netbird/client/iface/wgproxy/listener"
 )
 
@@ -135,7 +136,7 @@ func (p *ProxyBind) proxyToLocal(ctx context.Context) {
 	}()
 
 	for {
-		buf := make([]byte, 1500)
+		buf := make([]byte, p.Bind.MTU()+bufsize.WGBufferOverhead)
 		n, err := p.remoteConn.Read(buf)
 		if err != nil {
 			if ctx.Err() != nil {

client/iface/wgproxy/ebpf/proxy.go

@@ -17,6 +17,7 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	nberrors "github.com/netbirdio/netbird/client/errors"
+	"github.com/netbirdio/netbird/client/iface/bufsize"
 	"github.com/netbirdio/netbird/client/internal/ebpf"
 	ebpfMgr "github.com/netbirdio/netbird/client/internal/ebpf/manager"
 	nbnet "github.com/netbirdio/netbird/util/net"
@@ -29,6 +30,7 @@ const (
 // WGEBPFProxy definition for proxy with EBPF support
 type WGEBPFProxy struct {
 	localWGListenPort int
+	mtu               uint16
 
 	ebpfManager   ebpfMgr.Manager
 	turnConnStore map[uint16]net.Conn
@@ -43,10 +45,11 @@ type WGEBPFProxy struct {
 }
 
 // NewWGEBPFProxy create new WGEBPFProxy instance
-func NewWGEBPFProxy(wgPort int) *WGEBPFProxy {
+func NewWGEBPFProxy(wgPort int, mtu uint16) *WGEBPFProxy {
 	log.Debugf("instantiate ebpf proxy")
 	wgProxy := &WGEBPFProxy{
 		localWGListenPort: wgPort,
+		mtu:               mtu,
 		ebpfManager:       ebpf.GetEbpfManagerInstance(),
 		turnConnStore:     make(map[uint16]net.Conn),
 	}
@@ -138,7 +141,7 @@ func (p *WGEBPFProxy) Free() error {
 // proxyToRemote read messages from local WireGuard interface and forward it to remote conn
 // From this go routine has only one instance.
 func (p *WGEBPFProxy) proxyToRemote() {
-	buf := make([]byte, 1500)
+	buf := make([]byte, p.mtu+bufsize.WGBufferOverhead)
 	for p.ctx.Err() == nil {
 		if err := p.readAndForwardPacket(buf); err != nil {
 			if p.ctx.Err() != nil {

client/iface/wgproxy/ebpf/proxy_test.go

@@ -7,7 +7,7 @@ import (
 )
 
 func TestWGEBPFProxy_connStore(t *testing.T) {
-	wgProxy := NewWGEBPFProxy(1)
+	wgProxy := NewWGEBPFProxy(1, 1280)
 
 	p, _ := wgProxy.storeTurnConn(nil)
 	if p != 1 {
@@ -27,7 +27,7 @@ func TestWGEBPFProxy_connStore(t *testing.T) {
 }
 
 func TestWGEBPFProxy_portCalculation_overflow(t *testing.T) {
-	wgProxy := NewWGEBPFProxy(1)
+	wgProxy := NewWGEBPFProxy(1, 1280)
 
 	_, _ = wgProxy.storeTurnConn(nil)
 	wgProxy.lastUsedPort = 65535
@@ -43,7 +43,7 @@ func TestWGEBPFProxy_portCalculation_overflow(t *testing.T) {
 }
 
 func TestWGEBPFProxy_portCalculation_maxConn(t *testing.T) {
-	wgProxy := NewWGEBPFProxy(1)
+	wgProxy := NewWGEBPFProxy(1, 1280)
 
 	for i := 0; i < 65535; i++ {
 		_, _ = wgProxy.storeTurnConn(nil)

client/iface/wgproxy/ebpf/wrapper.go

@@ -12,6 +12,7 @@ import (
 
 	log "github.com/sirupsen/logrus"
 
+	"github.com/netbirdio/netbird/client/iface/bufsize"
 	"github.com/netbirdio/netbird/client/iface/wgproxy/listener"
 )
 
@@ -103,7 +104,7 @@ func (e *ProxyWrapper) CloseConn() error {
 func (p *ProxyWrapper) proxyToLocal(ctx context.Context) {
 	defer p.WgeBPFProxy.removeTurnConn(uint16(p.wgEndpointAddr.Port))
 
-	buf := make([]byte, 1500)
+	buf := make([]byte, p.WgeBPFProxy.mtu+bufsize.WGBufferOverhead)
 	for {
 		n, err := p.readFromRemote(ctx, buf)
 		if err != nil {

client/iface/wgproxy/factory_kernel.go

@@ -11,16 +11,18 @@ import (
 
 type KernelFactory struct {
 	wgPort int
+	mtu    uint16
 
 	ebpfProxy *ebpf.WGEBPFProxy
 }
 
-func NewKernelFactory(wgPort int) *KernelFactory {
+func NewKernelFactory(wgPort int, mtu uint16) *KernelFactory {
 	f := &KernelFactory{
 		wgPort: wgPort,
+		mtu:    mtu,
 	}
 
-	ebpfProxy := ebpf.NewWGEBPFProxy(wgPort)
+	ebpfProxy := ebpf.NewWGEBPFProxy(wgPort, mtu)
 	if err := ebpfProxy.Listen(); err != nil {
 		log.Infof("WireGuard Proxy Factory will produce UDP proxy")
 		log.Warnf("failed to initialize ebpf proxy, fallback to user space proxy: %s", err)
@@ -33,7 +35,7 @@ func NewKernelFactory(wgPort int) *KernelFactory {
 
 func (w *KernelFactory) GetProxy() Proxy {
 	if w.ebpfProxy == nil {
-		return udpProxy.NewWGUDPProxy(w.wgPort)
+		return udpProxy.NewWGUDPProxy(w.wgPort, w.mtu)
 	}
 
 	return ebpf.NewProxyWrapper(w.ebpfProxy)

client/iface/wgproxy/factory_kernel_freebsd.go

@@ -9,19 +9,21 @@ import (
 // KernelFactory todo: check eBPF support on FreeBSD
 type KernelFactory struct {
 	wgPort int
+	mtu    uint16
 }
 
-func NewKernelFactory(wgPort int) *KernelFactory {
+func NewKernelFactory(wgPort int, mtu uint16) *KernelFactory {
 	log.Infof("WireGuard Proxy Factory will produce UDP proxy")
 	f := &KernelFactory{
 		wgPort: wgPort,
+		mtu:    mtu,
 	}
 
 	return f
 }
 
 func (w *KernelFactory) GetProxy() Proxy {
-	return udpProxy.NewWGUDPProxy(w.wgPort)
+	return udpProxy.NewWGUDPProxy(w.wgPort, w.mtu)
 }
 
 func (w *KernelFactory) Free() error {

client/iface/wgproxy/proxy_linux_test.go

@@ -16,7 +16,7 @@ func TestProxyCloseByRemoteConnEBPF(t *testing.T) {
 	}
 	ctx := context.Background()
 
-	ebpfProxy := ebpf.NewWGEBPFProxy(51831)
+	ebpfProxy := ebpf.NewWGEBPFProxy(51831, 1280)
 	if err := ebpfProxy.Listen(); err != nil {
 		t.Fatalf("failed to initialize ebpf proxy: %s", err)
 	}

client/iface/wgproxy/proxy_test.go

@@ -84,12 +84,12 @@ func TestProxyCloseByRemoteConn(t *testing.T) {
 	}{
 		{
 			name:  "userspace proxy",
-			proxy: udpProxy.NewWGUDPProxy(51830),
+			proxy: udpProxy.NewWGUDPProxy(51830, 1280),
 		},
 	}
 
 	if runtime.GOOS == "linux" && os.Getenv("GITHUB_ACTIONS") != "true" {
-		ebpfProxy := ebpf.NewWGEBPFProxy(51831)
+		ebpfProxy := ebpf.NewWGEBPFProxy(51831, 1280)
 		if err := ebpfProxy.Listen(); err != nil {
 			t.Fatalf("failed to initialize ebpf proxy: %s", err)
 		}

client/iface/wgproxy/udp/proxy.go

@@ -12,12 +12,14 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	cerrors "github.com/netbirdio/netbird/client/errors"
+	"github.com/netbirdio/netbird/client/iface/bufsize"
 	"github.com/netbirdio/netbird/client/iface/wgproxy/listener"
 )
 
 // WGUDPProxy proxies
 type WGUDPProxy struct {
 	localWGListenPort int
+	mtu               uint16
 
 	remoteConn net.Conn
 	localConn  net.Conn
@@ -34,10 +36,11 @@ type WGUDPProxy struct {
 }
 
 // NewWGUDPProxy instantiate a UDP based WireGuard proxy. This is not a thread safe implementation
-func NewWGUDPProxy(wgPort int) *WGUDPProxy {
+func NewWGUDPProxy(wgPort int, mtu uint16) *WGUDPProxy {
 	log.Debugf("Initializing new user space proxy with port %d", wgPort)
 	p := &WGUDPProxy{
 		localWGListenPort: wgPort,
+		mtu:               mtu,
 		closeListener:     listener.NewCloseListener(),
 	}
 	return p
@@ -144,7 +147,7 @@ func (p *WGUDPProxy) proxyToRemote(ctx context.Context) {
 		}
 	}()
 
-	buf := make([]byte, 1500)
+	buf := make([]byte, p.mtu+bufsize.WGBufferOverhead)
 	for ctx.Err() == nil {
 		n, err := p.localConn.Read(buf)
 		if err != nil {
@@ -179,7 +182,7 @@ func (p *WGUDPProxy) proxyToLocal(ctx context.Context) {
 		}
 	}()
 
-	buf := make([]byte, 1500)
+	buf := make([]byte, p.mtu+bufsize.WGBufferOverhead)
 	for {
 		n, err := p.remoteConnRead(ctx, buf)
 		if err != nil {

client/internal/auth/device_flow_test.go

@@ -3,15 +3,17 @@ package auth
 import (
 	"context"
 	"fmt"
-	"github.com/golang-jwt/jwt"
-	"github.com/netbirdio/netbird/client/internal"
-	"github.com/stretchr/testify/require"
 	"io"
 	"net/http"
 	"net/url"
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/internal"
 )
 
 type mockHTTPClient struct {

client/internal/connect.go

@@ -18,6 +18,7 @@ import (
 	"google.golang.org/grpc/codes"
 	gstatus "google.golang.org/grpc/status"
 
+	"github.com/netbirdio/netbird/client/iface"
 	"github.com/netbirdio/netbird/client/iface/device"
 	"github.com/netbirdio/netbird/client/internal/dns"
 	"github.com/netbirdio/netbird/client/internal/listener"
@@ -244,7 +245,15 @@ func (c *ConnectClient) run(mobileDependency MobileDependency, runningChan chan
 		c.statusRecorder.MarkSignalConnected()
 
 		relayURLs, token := parseRelayInfo(loginResp)
-		relayManager := relayClient.NewManager(engineCtx, relayURLs, myPrivateKey.PublicKey().String())
+		peerConfig := loginResp.GetPeerConfig()
+
+		engineConfig, err := createEngineConfig(myPrivateKey, c.config, peerConfig)
+		if err != nil {
+			log.Error(err)
+			return wrapErr(err)
+		}
+
+		relayManager := relayClient.NewManager(engineCtx, relayURLs, myPrivateKey.PublicKey().String(), engineConfig.MTU)
 		c.statusRecorder.SetRelayMgr(relayManager)
 		if len(relayURLs) > 0 {
 			if token != nil {
@@ -259,14 +268,6 @@ func (c *ConnectClient) run(mobileDependency MobileDependency, runningChan chan
 			}
 		}
 
-		peerConfig := loginResp.GetPeerConfig()
-
-		engineConfig, err := createEngineConfig(myPrivateKey, c.config, peerConfig)
-		if err != nil {
-			log.Error(err)
-			return wrapErr(err)
-		}
-
 		checks := loginResp.GetChecks()
 
 		c.engineMutex.Lock()
@@ -274,11 +275,12 @@ func (c *ConnectClient) run(mobileDependency MobileDependency, runningChan chan
 		c.engine.SetSyncResponsePersistence(c.persistSyncResponse)
 		c.engineMutex.Unlock()
 
-		if err := c.engine.Start(); err != nil {
+		if err := c.engine.Start(loginResp.GetNetbirdConfig(), c.config.ManagementURL); err != nil {
 			log.Errorf("error while starting Netbird Connection Engine: %s", err)
 			return wrapErr(err)
 		}
 
+
 		log.Infof("Netbird engine started, the IP is: %s", peerConfig.GetAddress())
 		state.Set(StatusConnected)
 
@@ -444,6 +446,8 @@ func createEngineConfig(key wgtypes.Key, config *profilemanager.Config, peerConf
 		BlockInbound:        config.BlockInbound,
 
 		LazyConnectionEnabled: config.LazyConnectionEnabled,
+
+		MTU: selectMTU(config.MTU, peerConfig.Mtu),
 	}
 
 	if config.PreSharedKey != "" {
@@ -466,6 +470,20 @@ func createEngineConfig(key wgtypes.Key, config *profilemanager.Config, peerConf
 	return engineConf, nil
 }
 
+func selectMTU(localMTU uint16, peerMTU int32) uint16 {
+	var finalMTU uint16 = iface.DefaultMTU
+	if localMTU > 0 {
+		finalMTU = localMTU
+	} else if peerMTU > 0 {
+		finalMTU = uint16(peerMTU)
+	}
+
+	// Set global DNS MTU
+	dns.SetCurrentMTU(finalMTU)
+
+	return finalMTU
+}
+
 // connectToSignal creates Signal Service client and established a connection
 func connectToSignal(ctx context.Context, wtConfig *mgmProto.NetbirdConfig, ourPrivateKey wgtypes.Key) (*signal.GrpcClient, error) {
 	var sigTLSEnabled bool

client/internal/dns/config/domains.go

@@ -0,0 +1,201 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"net/netip"
+	"net/url"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/shared/management/domain"
+	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
+)
+
+var (
+	ErrEmptyURL     = errors.New("empty URL")
+	ErrEmptyHost    = errors.New("empty host")
+	ErrIPNotAllowed = errors.New("IP address not allowed")
+)
+
+// ServerDomains represents the management server domains extracted from NetBird configuration
+type ServerDomains struct {
+	Signal domain.Domain
+	Relay  []domain.Domain
+	Flow   domain.Domain
+	Stuns  []domain.Domain
+	Turns  []domain.Domain
+}
+
+// ExtractFromNetbirdConfig extracts domain information from NetBird protobuf configuration
+func ExtractFromNetbirdConfig(config *mgmProto.NetbirdConfig) ServerDomains {
+	if config == nil {
+		return ServerDomains{}
+	}
+
+	domains := ServerDomains{}
+
+	domains.Signal = extractSignalDomain(config)
+	domains.Relay = extractRelayDomains(config)
+	domains.Flow = extractFlowDomain(config)
+	domains.Stuns = extractStunDomains(config)
+	domains.Turns = extractTurnDomains(config)
+
+	return domains
+}
+
+// ExtractValidDomain extracts a valid domain from a URL, filtering out IP addresses
+func ExtractValidDomain(rawURL string) (domain.Domain, error) {
+	if rawURL == "" {
+		return "", ErrEmptyURL
+	}
+
+	parsedURL, err := url.Parse(rawURL)
+	if err == nil {
+		if domain, err := extractFromParsedURL(parsedURL); err != nil || domain != "" {
+			return domain, err
+		}
+	}
+
+	return extractFromRawString(rawURL)
+}
+
+// extractFromParsedURL handles domain extraction from successfully parsed URLs
+func extractFromParsedURL(parsedURL *url.URL) (domain.Domain, error) {
+	if parsedURL.Hostname() != "" {
+		return extractDomainFromHost(parsedURL.Hostname())
+	}
+
+	if parsedURL.Opaque == "" || parsedURL.Scheme == "" {
+		return "", nil
+	}
+
+	// Handle URLs with opaque content (e.g., stun:host:port)
+	if strings.Contains(parsedURL.Scheme, ".") {
+		// This is likely "domain.com:port" being parsed as scheme:opaque
+		reconstructed := parsedURL.Scheme + ":" + parsedURL.Opaque
+		if host, _, err := net.SplitHostPort(reconstructed); err == nil {
+			return extractDomainFromHost(host)
+		}
+		return extractDomainFromHost(parsedURL.Scheme)
+	}
+
+	// Valid scheme with opaque content (e.g., stun:host:port)
+	host := parsedURL.Opaque
+	if queryIndex := strings.Index(host, "?"); queryIndex > 0 {
+		host = host[:queryIndex]
+	}
+
+	if hostOnly, _, err := net.SplitHostPort(host); err == nil {
+		return extractDomainFromHost(hostOnly)
+	}
+
+	return extractDomainFromHost(host)
+}
+
+// extractFromRawString handles domain extraction when URL parsing fails or returns no results
+func extractFromRawString(rawURL string) (domain.Domain, error) {
+	if host, _, err := net.SplitHostPort(rawURL); err == nil {
+		return extractDomainFromHost(host)
+	}
+
+	return extractDomainFromHost(rawURL)
+}
+
+// extractDomainFromHost extracts domain from a host string, filtering out IP addresses
+func extractDomainFromHost(host string) (domain.Domain, error) {
+	if host == "" {
+		return "", ErrEmptyHost
+	}
+
+	if _, err := netip.ParseAddr(host); err == nil {
+		return "", fmt.Errorf("%w: %s", ErrIPNotAllowed, host)
+	}
+
+	d, err := domain.FromString(host)
+	if err != nil {
+		return "", fmt.Errorf("invalid domain: %v", err)
+	}
+
+	return d, nil
+}
+
+// extractSingleDomain extracts a single domain from a URL with error logging
+func extractSingleDomain(url, serviceType string) domain.Domain {
+	if url == "" {
+		return ""
+	}
+
+	d, err := ExtractValidDomain(url)
+	if err != nil {
+		log.Debugf("Skipping %s: %v", serviceType, err)
+		return ""
+	}
+
+	return d
+}
+
+// extractMultipleDomains extracts multiple domains from URLs with error logging
+func extractMultipleDomains(urls []string, serviceType string) []domain.Domain {
+	var domains []domain.Domain
+	for _, url := range urls {
+		if url == "" {
+			continue
+		}
+		d, err := ExtractValidDomain(url)
+		if err != nil {
+			log.Debugf("Skipping %s: %v", serviceType, err)
+			continue
+		}
+		domains = append(domains, d)
+	}
+	return domains
+}
+
+// extractSignalDomain extracts the signal domain from NetBird configuration.
+func extractSignalDomain(config *mgmProto.NetbirdConfig) domain.Domain {
+	if config.Signal != nil {
+		return extractSingleDomain(config.Signal.Uri, "signal")
+	}
+	return ""
+}
+
+// extractRelayDomains extracts relay server domains from NetBird configuration.
+func extractRelayDomains(config *mgmProto.NetbirdConfig) []domain.Domain {
+	if config.Relay != nil {
+		return extractMultipleDomains(config.Relay.Urls, "relay")
+	}
+	return nil
+}
+
+// extractFlowDomain extracts the traffic flow domain from NetBird configuration.
+func extractFlowDomain(config *mgmProto.NetbirdConfig) domain.Domain {
+	if config.Flow != nil {
+		return extractSingleDomain(config.Flow.Url, "flow")
+	}
+	return ""
+}
+
+// extractStunDomains extracts STUN server domains from NetBird configuration.
+func extractStunDomains(config *mgmProto.NetbirdConfig) []domain.Domain {
+	var urls []string
+	for _, stun := range config.Stuns {
+		if stun != nil && stun.Uri != "" {
+			urls = append(urls, stun.Uri)
+		}
+	}
+	return extractMultipleDomains(urls, "STUN")
+}
+
+// extractTurnDomains extracts TURN server domains from NetBird configuration.
+func extractTurnDomains(config *mgmProto.NetbirdConfig) []domain.Domain {
+	var urls []string
+	for _, turn := range config.Turns {
+		if turn != nil && turn.HostConfig != nil && turn.HostConfig.Uri != "" {
+			urls = append(urls, turn.HostConfig.Uri)
+		}
+	}
+	return extractMultipleDomains(urls, "TURN")
+}

client/internal/dns/config/domains_test.go

@@ -0,0 +1,213 @@
+package config
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestExtractValidDomain(t *testing.T) {
+	tests := []struct {
+		name        string
+		url         string
+		expected    string
+		expectError bool
+	}{
+		{
+			name:     "HTTPS URL with port",
+			url:      "https://api.netbird.io:443",
+			expected: "api.netbird.io",
+		},
+		{
+			name:     "HTTP URL without port",
+			url:      "http://signal.example.com",
+			expected: "signal.example.com",
+		},
+		{
+			name:     "Host with port (no scheme)",
+			url:      "signal.netbird.io:443",
+			expected: "signal.netbird.io",
+		},
+		{
+			name:     "STUN URL",
+			url:      "stun:stun.netbird.io:443",
+			expected: "stun.netbird.io",
+		},
+		{
+			name:     "STUN URL with different port",
+			url:      "stun:stun.netbird.io:5555",
+			expected: "stun.netbird.io",
+		},
+		{
+			name:     "TURNS URL with query params",
+			url:      "turns:turn.netbird.io:443?transport=tcp",
+			expected: "turn.netbird.io",
+		},
+		{
+			name:     "TURN URL",
+			url:      "turn:turn.example.com:3478",
+			expected: "turn.example.com",
+		},
+		{
+			name:     "REL URL",
+			url:      "rel://relay.example.com:443",
+			expected: "relay.example.com",
+		},
+		{
+			name:     "RELS URL",
+			url:      "rels://relay.netbird.io:443",
+			expected: "relay.netbird.io",
+		},
+		{
+			name:     "Raw hostname",
+			url:      "example.org",
+			expected: "example.org",
+		},
+		{
+			name:        "IP address should be rejected",
+			url:         "192.168.1.1",
+			expectError: true,
+		},
+		{
+			name:        "IP address with port should be rejected",
+			url:         "192.168.1.1:443",
+			expectError: true,
+		},
+		{
+			name:        "IPv6 address should be rejected",
+			url:         "2001:db8::1",
+			expectError: true,
+		},
+		{
+			name:        "HTTP URL with IPv4 should be rejected",
+			url:         "http://192.168.1.1:8080",
+			expectError: true,
+		},
+		{
+			name:        "HTTPS URL with IPv4 should be rejected",
+			url:         "https://10.0.0.1:443",
+			expectError: true,
+		},
+		{
+			name:        "STUN URL with IPv4 should be rejected",
+			url:         "stun:192.168.1.1:3478",
+			expectError: true,
+		},
+		{
+			name:        "TURN URL with IPv4 should be rejected",
+			url:         "turn:10.0.0.1:3478",
+			expectError: true,
+		},
+		{
+			name:        "TURNS URL with IPv4 should be rejected",
+			url:         "turns:172.16.0.1:5349",
+			expectError: true,
+		},
+		{
+			name:        "HTTP URL with IPv6 should be rejected",
+			url:         "http://[2001:db8::1]:8080",
+			expectError: true,
+		},
+		{
+			name:        "HTTPS URL with IPv6 should be rejected",
+			url:         "https://[::1]:443",
+			expectError: true,
+		},
+		{
+			name:        "STUN URL with IPv6 should be rejected",
+			url:         "stun:[2001:db8::1]:3478",
+			expectError: true,
+		},
+		{
+			name:        "IPv6 with port should be rejected",
+			url:         "[2001:db8::1]:443",
+			expectError: true,
+		},
+		{
+			name:        "Localhost IPv4 should be rejected",
+			url:         "127.0.0.1:8080",
+			expectError: true,
+		},
+		{
+			name:        "Localhost IPv6 should be rejected",
+			url:         "[::1]:443",
+			expectError: true,
+		},
+		{
+			name:        "REL URL with IPv4 should be rejected",
+			url:         "rel://192.168.1.1:443",
+			expectError: true,
+		},
+		{
+			name:        "RELS URL with IPv4 should be rejected",
+			url:         "rels://10.0.0.1:443",
+			expectError: true,
+		},
+		{
+			name:        "Empty URL",
+			url:         "",
+			expectError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result, err := ExtractValidDomain(tt.url)
+
+			if tt.expectError {
+				assert.Error(t, err, "Expected error for URL: %s", tt.url)
+			} else {
+				assert.NoError(t, err, "Unexpected error for URL: %s", tt.url)
+				assert.Equal(t, tt.expected, result.SafeString(), "Domain mismatch for URL: %s", tt.url)
+			}
+		})
+	}
+}
+
+func TestExtractDomainFromHost(t *testing.T) {
+	tests := []struct {
+		name        string
+		host        string
+		expected    string
+		expectError bool
+	}{
+		{
+			name:     "Valid domain",
+			host:     "example.com",
+			expected: "example.com",
+		},
+		{
+			name:     "Subdomain",
+			host:     "api.example.com",
+			expected: "api.example.com",
+		},
+		{
+			name:        "IPv4 address",
+			host:        "192.168.1.1",
+			expectError: true,
+		},
+		{
+			name:        "IPv6 address",
+			host:        "2001:db8::1",
+			expectError: true,
+		},
+		{
+			name:        "Empty host",
+			host:        "",
+			expectError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result, err := extractDomainFromHost(tt.host)
+
+			if tt.expectError {
+				assert.Error(t, err, "Expected error for host: %s", tt.host)
+			} else {
+				assert.NoError(t, err, "Unexpected error for host: %s", tt.host)
+				assert.Equal(t, tt.expected, result.SafeString(), "Domain mismatch for host: %s", tt.host)
+			}
+		})
+	}
+}

client/internal/dns/handler_chain.go

@@ -11,11 +11,12 @@ import (
 )
 
 const (
-	PriorityLocal    = 100
-	PriorityDNSRoute = 75
-	PriorityUpstream = 50
-	PriorityDefault  = 1
-	PriorityFallback = -100
+	PriorityMgmtCache = 150
+	PriorityLocal     = 100
+	PriorityDNSRoute  = 75
+	PriorityUpstream  = 50
+	PriorityDefault   = 1
+	PriorityFallback  = -100
 )
 
 type SubdomainMatcher interface {
@@ -182,7 +183,10 @@ func (c *HandlerChain) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 
 			// If handler wants to continue, try next handler
 			if chainWriter.shouldContinue {
-				log.Tracef("handler requested continue to next handler for domain=%s", qname)
+				// Only log continue for non-management cache handlers to reduce noise
+				if entry.Priority != PriorityMgmtCache {
+					log.Tracef("handler requested continue to next handler for domain=%s", qname)
+				}
 				continue
 			}
 			return

client/internal/dns/host_darwin.go

@@ -166,9 +166,10 @@ func (s *systemConfigurator) removeKeyFromSystemConfig(key string) error {
 
 func (s *systemConfigurator) addLocalDNS() error {
 	if !s.systemDNSSettings.ServerIP.IsValid() || len(s.systemDNSSettings.Domains) == 0 {
-		err := s.recordSystemDNSSettings(true)
-		log.Errorf("Unable to get system DNS configuration")
-		return err
+		if err := s.recordSystemDNSSettings(true); err != nil {
+			log.Errorf("Unable to get system DNS configuration")
+			return fmt.Errorf("recordSystemDNSSettings(): %w", err)
+		}
 	}
 	localKey := getKeyWithInput(netbirdDNSStateKeyFormat, localSuffix)
 	if s.systemDNSSettings.ServerIP.IsValid() && len(s.systemDNSSettings.Domains) != 0 {

client/internal/dns/local/local.go

@@ -34,7 +34,7 @@ func (d *Resolver) MatchSubdomains() bool {
 
 // String returns a string representation of the local resolver
 func (d *Resolver) String() string {
-	return fmt.Sprintf("local resolver [%d records]", len(d.records))
+	return fmt.Sprintf("LocalResolver [%d records]", len(d.records))
 }
 
 func (d *Resolver) Stop() {}

client/internal/dns/mgmt/mgmt.go

@@ -0,0 +1,360 @@
+package mgmt
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/url"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/miekg/dns"
+	log "github.com/sirupsen/logrus"
+
+	dnsconfig "github.com/netbirdio/netbird/client/internal/dns/config"
+	"github.com/netbirdio/netbird/shared/management/domain"
+)
+
+const dnsTimeout = 5 * time.Second
+
+// Resolver caches critical NetBird infrastructure domains
+type Resolver struct {
+	records       map[dns.Question][]dns.RR
+	mgmtDomain    *domain.Domain
+	serverDomains *dnsconfig.ServerDomains
+	mutex         sync.RWMutex
+}
+
+// NewResolver creates a new management domains cache resolver.
+func NewResolver() *Resolver {
+	return &Resolver{
+		records: make(map[dns.Question][]dns.RR),
+	}
+}
+
+// String returns a string representation of the resolver.
+func (m *Resolver) String() string {
+	return "MgmtCacheResolver"
+}
+
+// ServeDNS implements dns.Handler interface.
+func (m *Resolver) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
+	if len(r.Question) == 0 {
+		m.continueToNext(w, r)
+		return
+	}
+
+	question := r.Question[0]
+	question.Name = strings.ToLower(dns.Fqdn(question.Name))
+
+	if question.Qtype != dns.TypeA && question.Qtype != dns.TypeAAAA {
+		m.continueToNext(w, r)
+		return
+	}
+
+	m.mutex.RLock()
+	records, found := m.records[question]
+	m.mutex.RUnlock()
+
+	if !found {
+		m.continueToNext(w, r)
+		return
+	}
+
+	resp := &dns.Msg{}
+	resp.SetReply(r)
+	resp.Authoritative = false
+	resp.RecursionAvailable = true
+
+	resp.Answer = append(resp.Answer, records...)
+
+	log.Debugf("serving %d cached records for domain=%s", len(resp.Answer), question.Name)
+
+	if err := w.WriteMsg(resp); err != nil {
+		log.Errorf("failed to write response: %v", err)
+	}
+}
+
+// MatchSubdomains returns false since this resolver only handles exact domain matches
+// for NetBird infrastructure domains (signal, relay, flow, etc.), not their subdomains.
+func (m *Resolver) MatchSubdomains() bool {
+	return false
+}
+
+// continueToNext signals the handler chain to continue to the next handler.
+func (m *Resolver) continueToNext(w dns.ResponseWriter, r *dns.Msg) {
+	resp := &dns.Msg{}
+	resp.SetRcode(r, dns.RcodeNameError)
+	resp.MsgHdr.Zero = true
+	if err := w.WriteMsg(resp); err != nil {
+		log.Errorf("failed to write continue signal: %v", err)
+	}
+}
+
+// AddDomain manually adds a domain to cache by resolving it.
+func (m *Resolver) AddDomain(ctx context.Context, d domain.Domain) error {
+	dnsName := strings.ToLower(dns.Fqdn(d.PunycodeString()))
+
+	ctx, cancel := context.WithTimeout(ctx, dnsTimeout)
+	defer cancel()
+
+	ips, err := net.DefaultResolver.LookupNetIP(ctx, "ip", d.PunycodeString())
+	if err != nil {
+		return fmt.Errorf("resolve domain %s: %w", d.SafeString(), err)
+	}
+
+	var aRecords, aaaaRecords []dns.RR
+	for _, ip := range ips {
+		if ip.Is4() {
+			rr := &dns.A{
+				Hdr: dns.RR_Header{
+					Name:   dnsName,
+					Rrtype: dns.TypeA,
+					Class:  dns.ClassINET,
+					Ttl:    300,
+				},
+				A: ip.AsSlice(),
+			}
+			aRecords = append(aRecords, rr)
+		} else if ip.Is6() {
+			rr := &dns.AAAA{
+				Hdr: dns.RR_Header{
+					Name:   dnsName,
+					Rrtype: dns.TypeAAAA,
+					Class:  dns.ClassINET,
+					Ttl:    300,
+				},
+				AAAA: ip.AsSlice(),
+			}
+			aaaaRecords = append(aaaaRecords, rr)
+		}
+	}
+
+	m.mutex.Lock()
+
+	if len(aRecords) > 0 {
+		aQuestion := dns.Question{
+			Name:   dnsName,
+			Qtype:  dns.TypeA,
+			Qclass: dns.ClassINET,
+		}
+		m.records[aQuestion] = aRecords
+	}
+
+	if len(aaaaRecords) > 0 {
+		aaaaQuestion := dns.Question{
+			Name:   dnsName,
+			Qtype:  dns.TypeAAAA,
+			Qclass: dns.ClassINET,
+		}
+		m.records[aaaaQuestion] = aaaaRecords
+	}
+
+	m.mutex.Unlock()
+
+	log.Debugf("added domain=%s with %d A records and %d AAAA records",
+		d.SafeString(), len(aRecords), len(aaaaRecords))
+
+	return nil
+}
+
+// PopulateFromConfig extracts and caches domains from the client configuration.
+func (m *Resolver) PopulateFromConfig(ctx context.Context, mgmtURL *url.URL) error {
+	if mgmtURL == nil {
+		return nil
+	}
+
+	d, err := dnsconfig.ExtractValidDomain(mgmtURL.String())
+	if err != nil {
+		return fmt.Errorf("extract domain from URL: %w", err)
+	}
+
+	m.mutex.Lock()
+	m.mgmtDomain = &d
+	m.mutex.Unlock()
+
+	if err := m.AddDomain(ctx, d); err != nil {
+		return fmt.Errorf("add domain: %w", err)
+	}
+
+	return nil
+}
+
+// RemoveDomain removes a domain from the cache.
+func (m *Resolver) RemoveDomain(d domain.Domain) error {
+	dnsName := strings.ToLower(dns.Fqdn(d.PunycodeString()))
+
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	aQuestion := dns.Question{
+		Name:   dnsName,
+		Qtype:  dns.TypeA,
+		Qclass: dns.ClassINET,
+	}
+	delete(m.records, aQuestion)
+
+	aaaaQuestion := dns.Question{
+		Name:   dnsName,
+		Qtype:  dns.TypeAAAA,
+		Qclass: dns.ClassINET,
+	}
+	delete(m.records, aaaaQuestion)
+
+	log.Debugf("removed domain=%s from cache", d.SafeString())
+	return nil
+}
+
+// GetCachedDomains returns a list of all cached domains.
+func (m *Resolver) GetCachedDomains() domain.List {
+	m.mutex.RLock()
+	defer m.mutex.RUnlock()
+
+	domainSet := make(map[domain.Domain]struct{})
+	for question := range m.records {
+		domainName := strings.TrimSuffix(question.Name, ".")
+		domainSet[domain.Domain(domainName)] = struct{}{}
+	}
+
+	domains := make(domain.List, 0, len(domainSet))
+	for d := range domainSet {
+		domains = append(domains, d)
+	}
+
+	return domains
+}
+
+// UpdateFromServerDomains updates the cache with server domains from network configuration.
+// It merges new domains with existing ones, replacing entire domain types when updated.
+// Empty updates are ignored to prevent clearing infrastructure domains during partial updates.
+func (m *Resolver) UpdateFromServerDomains(ctx context.Context, serverDomains dnsconfig.ServerDomains) (domain.List, error) {
+	newDomains := m.extractDomainsFromServerDomains(serverDomains)
+	var removedDomains domain.List
+
+	if len(newDomains) > 0 {
+		m.mutex.Lock()
+		if m.serverDomains == nil {
+			m.serverDomains = &dnsconfig.ServerDomains{}
+		}
+		updatedServerDomains := m.mergeServerDomains(*m.serverDomains, serverDomains)
+		m.serverDomains = &updatedServerDomains
+		m.mutex.Unlock()
+
+		allDomains := m.extractDomainsFromServerDomains(updatedServerDomains)
+		currentDomains := m.GetCachedDomains()
+		removedDomains = m.removeStaleDomains(currentDomains, allDomains)
+	}
+
+	m.addNewDomains(ctx, newDomains)
+
+	return removedDomains, nil
+}
+
+// removeStaleDomains removes cached domains not present in the target domain list.
+// Management domains are preserved and never removed during server domain updates.
+func (m *Resolver) removeStaleDomains(currentDomains, newDomains domain.List) domain.List {
+	var removedDomains domain.List
+
+	for _, currentDomain := range currentDomains {
+		if m.isDomainInList(currentDomain, newDomains) {
+			continue
+		}
+
+		if m.isManagementDomain(currentDomain) {
+			continue
+		}
+
+		removedDomains = append(removedDomains, currentDomain)
+		if err := m.RemoveDomain(currentDomain); err != nil {
+			log.Warnf("failed to remove domain=%s: %v", currentDomain.SafeString(), err)
+		}
+	}
+
+	return removedDomains
+}
+
+// mergeServerDomains merges new server domains with existing ones.
+// When a domain type is provided in the new domains, it completely replaces that type.
+func (m *Resolver) mergeServerDomains(existing, incoming dnsconfig.ServerDomains) dnsconfig.ServerDomains {
+	merged := existing
+
+	if incoming.Signal != "" {
+		merged.Signal = incoming.Signal
+	}
+	if len(incoming.Relay) > 0 {
+		merged.Relay = incoming.Relay
+	}
+	if incoming.Flow != "" {
+		merged.Flow = incoming.Flow
+	}
+	if len(incoming.Stuns) > 0 {
+		merged.Stuns = incoming.Stuns
+	}
+	if len(incoming.Turns) > 0 {
+		merged.Turns = incoming.Turns
+	}
+
+	return merged
+}
+
+// isDomainInList checks if domain exists in the list
+func (m *Resolver) isDomainInList(domain domain.Domain, list domain.List) bool {
+	for _, d := range list {
+		if domain.SafeString() == d.SafeString() {
+			return true
+		}
+	}
+	return false
+}
+
+// isManagementDomain checks if domain is the protected management domain
+func (m *Resolver) isManagementDomain(domain domain.Domain) bool {
+	m.mutex.RLock()
+	defer m.mutex.RUnlock()
+
+	return m.mgmtDomain != nil && domain == *m.mgmtDomain
+}
+
+// addNewDomains resolves and caches all domains from the update
+func (m *Resolver) addNewDomains(ctx context.Context, newDomains domain.List) {
+	for _, newDomain := range newDomains {
+		if err := m.AddDomain(ctx, newDomain); err != nil {
+			log.Warnf("failed to add/update domain=%s: %v", newDomain.SafeString(), err)
+		} else {
+			log.Debugf("added/updated management cache domain=%s", newDomain.SafeString())
+		}
+	}
+}
+
+func (m *Resolver) extractDomainsFromServerDomains(serverDomains dnsconfig.ServerDomains) domain.List {
+	var domains domain.List
+
+	if serverDomains.Signal != "" {
+		domains = append(domains, serverDomains.Signal)
+	}
+
+	for _, relay := range serverDomains.Relay {
+		if relay != "" {
+			domains = append(domains, relay)
+		}
+	}
+
+	if serverDomains.Flow != "" {
+		domains = append(domains, serverDomains.Flow)
+	}
+
+	for _, stun := range serverDomains.Stuns {
+		if stun != "" {
+			domains = append(domains, stun)
+		}
+	}
+
+	for _, turn := range serverDomains.Turns {
+		if turn != "" {
+			domains = append(domains, turn)
+		}
+	}
+
+	return domains
+}

client/internal/dns/mgmt/mgmt_test.go

@@ -0,0 +1,416 @@
+package mgmt
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"strings"
+	"testing"
+
+	"github.com/miekg/dns"
+	"github.com/stretchr/testify/assert"
+
+	dnsconfig "github.com/netbirdio/netbird/client/internal/dns/config"
+	"github.com/netbirdio/netbird/client/internal/dns/test"
+	"github.com/netbirdio/netbird/shared/management/domain"
+)
+
+func TestResolver_NewResolver(t *testing.T) {
+	resolver := NewResolver()
+
+	assert.NotNil(t, resolver)
+	assert.NotNil(t, resolver.records)
+	assert.False(t, resolver.MatchSubdomains())
+}
+
+func TestResolver_ExtractDomainFromURL(t *testing.T) {
+	tests := []struct {
+		name        string
+		urlStr      string
+		expectedDom string
+		expectError bool
+	}{
+		{
+			name:        "HTTPS URL with port",
+			urlStr:      "https://api.netbird.io:443",
+			expectedDom: "api.netbird.io",
+			expectError: false,
+		},
+		{
+			name:        "HTTP URL without port",
+			urlStr:      "http://signal.example.com",
+			expectedDom: "signal.example.com",
+			expectError: false,
+		},
+		{
+			name:        "URL with path",
+			urlStr:      "https://relay.netbird.io/status",
+			expectedDom: "relay.netbird.io",
+			expectError: false,
+		},
+		{
+			name:        "Invalid URL",
+			urlStr:      "not-a-valid-url",
+			expectedDom: "not-a-valid-url",
+			expectError: false,
+		},
+		{
+			name:        "Empty URL",
+			urlStr:      "",
+			expectedDom: "",
+			expectError: true,
+		},
+		{
+			name:        "STUN URL",
+			urlStr:      "stun:stun.example.com:3478",
+			expectedDom: "stun.example.com",
+			expectError: false,
+		},
+		{
+			name:        "TURN URL",
+			urlStr:      "turn:turn.example.com:3478",
+			expectedDom: "turn.example.com",
+			expectError: false,
+		},
+		{
+			name:        "REL URL",
+			urlStr:      "rel://relay.example.com:443",
+			expectedDom: "relay.example.com",
+			expectError: false,
+		},
+		{
+			name:        "RELS URL",
+			urlStr:      "rels://relay.example.com:443",
+			expectedDom: "relay.example.com",
+			expectError: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var parsedURL *url.URL
+			var err error
+
+			if tt.urlStr != "" {
+				parsedURL, err = url.Parse(tt.urlStr)
+				if err != nil && !tt.expectError {
+					t.Fatalf("Failed to parse URL: %v", err)
+				}
+			}
+
+			domain, err := extractDomainFromURL(parsedURL)
+
+			if tt.expectError {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.expectedDom, domain.SafeString())
+			}
+		})
+	}
+}
+
+func TestResolver_PopulateFromConfig(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	resolver := NewResolver()
+
+	// Test with IP address - should return error since IP addresses are rejected
+	mgmtURL, _ := url.Parse("https://127.0.0.1")
+
+	err := resolver.PopulateFromConfig(ctx, mgmtURL)
+	assert.Error(t, err)
+	assert.ErrorIs(t, err, dnsconfig.ErrIPNotAllowed)
+
+	// No domains should be cached when using IP addresses
+	domains := resolver.GetCachedDomains()
+	assert.Equal(t, 0, len(domains), "No domains should be cached when using IP addresses")
+}
+
+func TestResolver_ServeDNS(t *testing.T) {
+	resolver := NewResolver()
+	ctx := context.Background()
+
+	// Add a test domain to the cache - use example.org which is reserved for testing
+	testDomain, err := domain.FromString("example.org")
+	if err != nil {
+		t.Fatalf("Failed to create domain: %v", err)
+	}
+	err = resolver.AddDomain(ctx, testDomain)
+	if err != nil {
+		t.Skipf("Skipping test due to DNS resolution failure: %v", err)
+	}
+
+	// Test A record query for cached domain
+	t.Run("Cached domain A record", func(t *testing.T) {
+		var capturedMsg *dns.Msg
+		mockWriter := &test.MockResponseWriter{
+			WriteMsgFunc: func(m *dns.Msg) error {
+				capturedMsg = m
+				return nil
+			},
+		}
+
+		req := new(dns.Msg)
+		req.SetQuestion("example.org.", dns.TypeA)
+
+		resolver.ServeDNS(mockWriter, req)
+
+		assert.NotNil(t, capturedMsg)
+		assert.Equal(t, dns.RcodeSuccess, capturedMsg.Rcode)
+		assert.True(t, len(capturedMsg.Answer) > 0, "Should have at least one answer")
+	})
+
+	// Test uncached domain signals to continue to next handler
+	t.Run("Uncached domain signals continue to next handler", func(t *testing.T) {
+		var capturedMsg *dns.Msg
+		mockWriter := &test.MockResponseWriter{
+			WriteMsgFunc: func(m *dns.Msg) error {
+				capturedMsg = m
+				return nil
+			},
+		}
+
+		req := new(dns.Msg)
+		req.SetQuestion("unknown.example.com.", dns.TypeA)
+
+		resolver.ServeDNS(mockWriter, req)
+
+		assert.NotNil(t, capturedMsg)
+		assert.Equal(t, dns.RcodeNameError, capturedMsg.Rcode)
+		// Zero flag set to true signals the handler chain to continue to next handler
+		assert.True(t, capturedMsg.MsgHdr.Zero, "Zero flag should be set to signal continuation to next handler")
+		assert.Empty(t, capturedMsg.Answer, "Should have no answers for uncached domain")
+	})
+
+	// Test that subdomains of cached domains are NOT resolved
+	t.Run("Subdomains of cached domains are not resolved", func(t *testing.T) {
+		var capturedMsg *dns.Msg
+		mockWriter := &test.MockResponseWriter{
+			WriteMsgFunc: func(m *dns.Msg) error {
+				capturedMsg = m
+				return nil
+			},
+		}
+
+		// Query for a subdomain of our cached domain
+		req := new(dns.Msg)
+		req.SetQuestion("sub.example.org.", dns.TypeA)
+
+		resolver.ServeDNS(mockWriter, req)
+
+		assert.NotNil(t, capturedMsg)
+		assert.Equal(t, dns.RcodeNameError, capturedMsg.Rcode)
+		assert.True(t, capturedMsg.MsgHdr.Zero, "Should signal continuation to next handler for subdomains")
+		assert.Empty(t, capturedMsg.Answer, "Should have no answers for subdomains")
+	})
+
+	// Test case-insensitive matching
+	t.Run("Case-insensitive domain matching", func(t *testing.T) {
+		var capturedMsg *dns.Msg
+		mockWriter := &test.MockResponseWriter{
+			WriteMsgFunc: func(m *dns.Msg) error {
+				capturedMsg = m
+				return nil
+			},
+		}
+
+		// Query with different casing
+		req := new(dns.Msg)
+		req.SetQuestion("EXAMPLE.ORG.", dns.TypeA)
+
+		resolver.ServeDNS(mockWriter, req)
+
+		assert.NotNil(t, capturedMsg)
+		assert.Equal(t, dns.RcodeSuccess, capturedMsg.Rcode)
+		assert.True(t, len(capturedMsg.Answer) > 0, "Should resolve regardless of case")
+	})
+}
+
+func TestResolver_GetCachedDomains(t *testing.T) {
+	resolver := NewResolver()
+	ctx := context.Background()
+
+	testDomain, err := domain.FromString("example.org")
+	if err != nil {
+		t.Fatalf("Failed to create domain: %v", err)
+	}
+	err = resolver.AddDomain(ctx, testDomain)
+	if err != nil {
+		t.Skipf("Skipping test due to DNS resolution failure: %v", err)
+	}
+
+	cachedDomains := resolver.GetCachedDomains()
+
+	assert.Equal(t, 1, len(cachedDomains), "Should return exactly one domain for single added domain")
+	assert.Equal(t, testDomain.SafeString(), cachedDomains[0].SafeString(), "Cached domain should match original")
+	assert.False(t, strings.HasSuffix(cachedDomains[0].PunycodeString(), "."), "Domain should not have trailing dot")
+}
+
+func TestResolver_ManagementDomainProtection(t *testing.T) {
+	resolver := NewResolver()
+	ctx := context.Background()
+
+	mgmtURL, _ := url.Parse("https://example.org")
+	err := resolver.PopulateFromConfig(ctx, mgmtURL)
+	if err != nil {
+		t.Skipf("Skipping test due to DNS resolution failure: %v", err)
+	}
+
+	initialDomains := resolver.GetCachedDomains()
+	if len(initialDomains) == 0 {
+		t.Skip("Management domain failed to resolve, skipping test")
+	}
+	assert.Equal(t, 1, len(initialDomains), "Should have management domain cached")
+	assert.Equal(t, "example.org", initialDomains[0].SafeString())
+
+	serverDomains := dnsconfig.ServerDomains{
+		Signal: "google.com",
+		Relay:  []domain.Domain{"cloudflare.com"},
+	}
+
+	_, err = resolver.UpdateFromServerDomains(ctx, serverDomains)
+	if err != nil {
+		t.Logf("Server domains update failed: %v", err)
+	}
+
+	finalDomains := resolver.GetCachedDomains()
+
+	managementStillCached := false
+	for _, d := range finalDomains {
+		if d.SafeString() == "example.org" {
+			managementStillCached = true
+			break
+		}
+	}
+	assert.True(t, managementStillCached, "Management domain should never be removed")
+}
+
+// extractDomainFromURL extracts a domain from a URL - test helper function
+func extractDomainFromURL(u *url.URL) (domain.Domain, error) {
+	if u == nil {
+		return "", fmt.Errorf("URL is nil")
+	}
+	return dnsconfig.ExtractValidDomain(u.String())
+}
+
+func TestResolver_EmptyUpdateDoesNotRemoveDomains(t *testing.T) {
+	resolver := NewResolver()
+	ctx := context.Background()
+
+	// Set up initial domains using resolvable domains
+	initialDomains := dnsconfig.ServerDomains{
+		Signal: "example.org",
+		Stuns:  []domain.Domain{"google.com"},
+		Turns:  []domain.Domain{"cloudflare.com"},
+	}
+
+	// Add initial domains
+	_, err := resolver.UpdateFromServerDomains(ctx, initialDomains)
+	if err != nil {
+		t.Skipf("Skipping test due to DNS resolution failure: %v", err)
+	}
+
+	// Verify domains were added
+	cachedDomains := resolver.GetCachedDomains()
+	assert.Len(t, cachedDomains, 3)
+
+	// Update with empty ServerDomains (simulating partial network map update)
+	emptyDomains := dnsconfig.ServerDomains{}
+	removedDomains, err := resolver.UpdateFromServerDomains(ctx, emptyDomains)
+	assert.NoError(t, err)
+
+	// Verify no domains were removed
+	assert.Len(t, removedDomains, 0, "No domains should be removed when update is empty")
+
+	// Verify all original domains are still cached
+	finalDomains := resolver.GetCachedDomains()
+	assert.Len(t, finalDomains, 3, "All original domains should still be cached")
+}
+
+func TestResolver_PartialUpdateReplacesOnlyUpdatedTypes(t *testing.T) {
+	resolver := NewResolver()
+	ctx := context.Background()
+
+	// Set up initial complete domains using resolvable domains
+	initialDomains := dnsconfig.ServerDomains{
+		Signal: "example.org",
+		Stuns:  []domain.Domain{"google.com"},
+		Turns:  []domain.Domain{"cloudflare.com"},
+	}
+
+	// Add initial domains
+	_, err := resolver.UpdateFromServerDomains(ctx, initialDomains)
+	if err != nil {
+		t.Skipf("Skipping test due to DNS resolution failure: %v", err)
+	}
+	assert.Len(t, resolver.GetCachedDomains(), 3)
+
+	// Update with partial ServerDomains (only signal domain - this should replace signal but preserve stun/turn)
+	partialDomains := dnsconfig.ServerDomains{
+		Signal: "github.com",
+	}
+	removedDomains, err := resolver.UpdateFromServerDomains(ctx, partialDomains)
+	if err != nil {
+		t.Skipf("Skipping test due to DNS resolution failure: %v", err)
+	}
+
+	// Should remove only the old signal domain
+	assert.Len(t, removedDomains, 1, "Should remove only the old signal domain")
+	assert.Equal(t, "example.org", removedDomains[0].SafeString())
+
+	finalDomains := resolver.GetCachedDomains()
+	assert.Len(t, finalDomains, 3, "Should have new signal plus preserved stun/turn domains")
+
+	domainStrings := make([]string, len(finalDomains))
+	for i, d := range finalDomains {
+		domainStrings[i] = d.SafeString()
+	}
+	assert.Contains(t, domainStrings, "github.com")
+	assert.Contains(t, domainStrings, "google.com")
+	assert.Contains(t, domainStrings, "cloudflare.com")
+	assert.NotContains(t, domainStrings, "example.org")
+}
+
+func TestResolver_PartialUpdateAddsNewTypePreservesExisting(t *testing.T) {
+	resolver := NewResolver()
+	ctx := context.Background()
+
+	// Set up initial complete domains using resolvable domains
+	initialDomains := dnsconfig.ServerDomains{
+		Signal: "example.org",
+		Stuns:  []domain.Domain{"google.com"},
+		Turns:  []domain.Domain{"cloudflare.com"},
+	}
+
+	// Add initial domains
+	_, err := resolver.UpdateFromServerDomains(ctx, initialDomains)
+	if err != nil {
+		t.Skipf("Skipping test due to DNS resolution failure: %v", err)
+	}
+	assert.Len(t, resolver.GetCachedDomains(), 3)
+
+	// Update with partial ServerDomains (only flow domain - new type, should preserve all existing)
+	partialDomains := dnsconfig.ServerDomains{
+		Flow: "github.com",
+	}
+	removedDomains, err := resolver.UpdateFromServerDomains(ctx, partialDomains)
+	if err != nil {
+		t.Skipf("Skipping test due to DNS resolution failure: %v", err)
+	}
+
+	assert.Len(t, removedDomains, 0, "Should not remove any domains when adding new type")
+
+	finalDomains := resolver.GetCachedDomains()
+	assert.Len(t, finalDomains, 4, "Should have all original domains plus new flow domain")
+
+	domainStrings := make([]string, len(finalDomains))
+	for i, d := range finalDomains {
+		domainStrings[i] = d.SafeString()
+	}
+	assert.Contains(t, domainStrings, "example.org")
+	assert.Contains(t, domainStrings, "google.com")
+	assert.Contains(t, domainStrings, "cloudflare.com")
+	assert.Contains(t, domainStrings, "github.com")
+}

client/internal/dns/mock_server.go

@@ -3,20 +3,23 @@ package dns
 import (
 	"fmt"
 	"net/netip"
+	"net/url"
 
 	"github.com/miekg/dns"
 
+	dnsconfig "github.com/netbirdio/netbird/client/internal/dns/config"
 	nbdns "github.com/netbirdio/netbird/dns"
 	"github.com/netbirdio/netbird/shared/management/domain"
 )
 
 // MockServer is the mock instance of a dns server
 type MockServer struct {
-	InitializeFunc        func() error
-	StopFunc              func()
-	UpdateDNSServerFunc   func(serial uint64, update nbdns.Config) error
-	RegisterHandlerFunc   func(domain.List, dns.Handler, int)
-	DeregisterHandlerFunc func(domain.List, int)
+	InitializeFunc         func() error
+	StopFunc               func()
+	UpdateDNSServerFunc    func(serial uint64, update nbdns.Config) error
+	RegisterHandlerFunc    func(domain.List, dns.Handler, int)
+	DeregisterHandlerFunc  func(domain.List, int)
+	UpdateServerConfigFunc func(domains dnsconfig.ServerDomains) error
 }
 
 func (m *MockServer) RegisterHandler(domains domain.List, handler dns.Handler, priority int) {
@@ -70,3 +73,14 @@ func (m *MockServer) SearchDomains() []string {
 // ProbeAvailability mocks implementation of ProbeAvailability from the Server interface
 func (m *MockServer) ProbeAvailability() {
 }
+
+func (m *MockServer) UpdateServerConfig(domains dnsconfig.ServerDomains) error {
+	if m.UpdateServerConfigFunc != nil {
+		return m.UpdateServerConfigFunc(domains)
+	}
+	return nil
+}
+
+func (m *MockServer) PopulateManagementDomain(mgmtURL *url.URL) error {
+	return nil
+}

client/internal/dns/server.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"net/netip"
+	"net/url"
 	"runtime"
 	"strings"
 	"sync"
@@ -15,7 +16,9 @@ import (
 	"golang.org/x/exp/maps"
 
 	"github.com/netbirdio/netbird/client/iface/netstack"
+	dnsconfig "github.com/netbirdio/netbird/client/internal/dns/config"
 	"github.com/netbirdio/netbird/client/internal/dns/local"
+	"github.com/netbirdio/netbird/client/internal/dns/mgmt"
 	"github.com/netbirdio/netbird/client/internal/dns/types"
 	"github.com/netbirdio/netbird/client/internal/listener"
 	"github.com/netbirdio/netbird/client/internal/peer"
@@ -45,6 +48,8 @@ type Server interface {
 	OnUpdatedHostDNSServer(addrs []netip.AddrPort)
 	SearchDomains() []string
 	ProbeAvailability()
+	UpdateServerConfig(domains dnsconfig.ServerDomains) error
+	PopulateManagementDomain(mgmtURL *url.URL) error
 }
 
 type nsGroupsByDomain struct {
@@ -77,6 +82,8 @@ type DefaultServer struct {
 	handlerChain       *HandlerChain
 	extraDomains       map[domain.Domain]int
 
+	mgmtCacheResolver *mgmt.Resolver
+
 	// permanent related properties
 	permanent      bool
 	hostsDNSHolder *hostsDNSHolder
@@ -104,18 +111,20 @@ type handlerWrapper struct {
 
 type registeredHandlerMap map[types.HandlerID]handlerWrapper
 
+// DefaultServerConfig holds configuration parameters for NewDefaultServer
+type DefaultServerConfig struct {
+	WgInterface    WGIface
+	CustomAddress  string
+	StatusRecorder *peer.Status
+	StateManager   *statemanager.Manager
+	DisableSys     bool
+}
+
 // NewDefaultServer returns a new dns server
-func NewDefaultServer(
-	ctx context.Context,
-	wgInterface WGIface,
-	customAddress string,
-	statusRecorder *peer.Status,
-	stateManager *statemanager.Manager,
-	disableSys bool,
-) (*DefaultServer, error) {
+func NewDefaultServer(ctx context.Context, config DefaultServerConfig) (*DefaultServer, error) {
 	var addrPort *netip.AddrPort
-	if customAddress != "" {
-		parsedAddrPort, err := netip.ParseAddrPort(customAddress)
+	if config.CustomAddress != "" {
+		parsedAddrPort, err := netip.ParseAddrPort(config.CustomAddress)
 		if err != nil {
 			return nil, fmt.Errorf("unable to parse the custom dns address, got error: %s", err)
 		}
@@ -123,13 +132,14 @@ func NewDefaultServer(
 	}
 
 	var dnsService service
-	if wgInterface.IsUserspaceBind() {
-		dnsService = NewServiceViaMemory(wgInterface)
+	if config.WgInterface.IsUserspaceBind() {
+		dnsService = NewServiceViaMemory(config.WgInterface)
 	} else {
-		dnsService = newServiceViaListener(wgInterface, addrPort)
+		dnsService = newServiceViaListener(config.WgInterface, addrPort)
 	}
 
-	return newDefaultServer(ctx, wgInterface, dnsService, statusRecorder, stateManager, disableSys), nil
+	server := newDefaultServer(ctx, config.WgInterface, dnsService, config.StatusRecorder, config.StateManager, config.DisableSys)
+	return server, nil
 }
 
 // NewDefaultServerPermanentUpstream returns a new dns server. It optimized for mobile systems
@@ -178,20 +188,24 @@ func newDefaultServer(
 ) *DefaultServer {
 	handlerChain := NewHandlerChain()
 	ctx, stop := context.WithCancel(ctx)
+
+	mgmtCacheResolver := mgmt.NewResolver()
+
 	defaultServer := &DefaultServer{
-		ctx:            ctx,
-		ctxCancel:      stop,
-		disableSys:     disableSys,
-		service:        dnsService,
-		handlerChain:   handlerChain,
-		extraDomains:   make(map[domain.Domain]int),
-		dnsMuxMap:      make(registeredHandlerMap),
-		localResolver:  local.NewResolver(),
-		wgInterface:    wgInterface,
-		statusRecorder: statusRecorder,
-		stateManager:   stateManager,
-		hostsDNSHolder: newHostsDNSHolder(),
-		hostManager:    &noopHostConfigurator{},
+		ctx:               ctx,
+		ctxCancel:         stop,
+		disableSys:        disableSys,
+		service:           dnsService,
+		handlerChain:      handlerChain,
+		extraDomains:      make(map[domain.Domain]int),
+		dnsMuxMap:         make(registeredHandlerMap),
+		localResolver:     local.NewResolver(),
+		wgInterface:       wgInterface,
+		statusRecorder:    statusRecorder,
+		stateManager:      stateManager,
+		hostsDNSHolder:    newHostsDNSHolder(),
+		hostManager:       &noopHostConfigurator{},
+		mgmtCacheResolver: mgmtCacheResolver,
 	}
 
 	// register with root zone, handler chain takes care of the routing
@@ -217,7 +231,7 @@ func (s *DefaultServer) RegisterHandler(domains domain.List, handler dns.Handler
 }
 
 func (s *DefaultServer) registerHandler(domains []string, handler dns.Handler, priority int) {
-	log.Debugf("registering handler %s with priority %d", handler, priority)
+	log.Debugf("registering handler %s with priority %d for %v", handler, priority, domains)
 
 	for _, domain := range domains {
 		if domain == "" {
@@ -246,7 +260,7 @@ func (s *DefaultServer) DeregisterHandler(domains domain.List, priority int) {
 }
 
 func (s *DefaultServer) deregisterHandler(domains []string, priority int) {
-	log.Debugf("deregistering handler %v with priority %d", domains, priority)
+	log.Debugf("deregistering handler with priority %d for %v", priority, domains)
 
 	for _, domain := range domains {
 		if domain == "" {
@@ -432,6 +446,29 @@ func (s *DefaultServer) ProbeAvailability() {
 	wg.Wait()
 }
 
+func (s *DefaultServer) UpdateServerConfig(domains dnsconfig.ServerDomains) error {
+	s.mux.Lock()
+	defer s.mux.Unlock()
+
+	if s.mgmtCacheResolver != nil {
+		removedDomains, err := s.mgmtCacheResolver.UpdateFromServerDomains(s.ctx, domains)
+		if err != nil {
+			return fmt.Errorf("update management cache resolver: %w", err)
+		}
+
+		if len(removedDomains) > 0 {
+			s.deregisterHandler(removedDomains.ToPunycodeList(), PriorityMgmtCache)
+		}
+
+		newDomains := s.mgmtCacheResolver.GetCachedDomains()
+		if len(newDomains) > 0 {
+			s.registerHandler(newDomains.ToPunycodeList(), s.mgmtCacheResolver, PriorityMgmtCache)
+		}
+	}
+
+	return nil
+}
+
 func (s *DefaultServer) applyConfiguration(update nbdns.Config) error {
 	// is the service should be Disabled, we stop the listener or fake resolver
 	if update.ServiceEnable {
@@ -961,3 +998,11 @@ func toZone(d domain.Domain) domain.Domain {
 		),
 	)
 }
+
+// PopulateManagementDomain populates the DNS cache with management domain
+func (s *DefaultServer) PopulateManagementDomain(mgmtURL *url.URL) error {
+	if s.mgmtCacheResolver != nil {
+		return s.mgmtCacheResolver.PopulateFromConfig(s.ctx, mgmtURL)
+	}
+	return nil
+}

client/internal/dns/server_test.go

@@ -363,7 +363,13 @@ func TestUpdateDNSServer(t *testing.T) {
 					t.Log(err)
 				}
 			}()
-			dnsServer, err := NewDefaultServer(context.Background(), wgIface, "", peer.NewRecorder("mgm"), nil, false)
+			dnsServer, err := NewDefaultServer(context.Background(), DefaultServerConfig{
+				WgInterface:    wgIface,
+				CustomAddress:  "",
+				StatusRecorder: peer.NewRecorder("mgm"),
+				StateManager:   nil,
+				DisableSys:     false,
+			})
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -473,7 +479,13 @@ func TestDNSFakeResolverHandleUpdates(t *testing.T) {
 		return
 	}
 
-	dnsServer, err := NewDefaultServer(context.Background(), wgIface, "", peer.NewRecorder("mgm"), nil, false)
+	dnsServer, err := NewDefaultServer(context.Background(), DefaultServerConfig{
+		WgInterface:    wgIface,
+		CustomAddress:  "",
+		StatusRecorder: peer.NewRecorder("mgm"),
+		StateManager:   nil,
+		DisableSys:     false,
+	})
 	if err != nil {
 		t.Errorf("create DNS server: %v", err)
 		return
@@ -575,7 +587,13 @@ func TestDNSServerStartStop(t *testing.T) {
 
 	for _, testCase := range testCases {
 		t.Run(testCase.name, func(t *testing.T) {
-			dnsServer, err := NewDefaultServer(context.Background(), &mocWGIface{}, testCase.addrPort, peer.NewRecorder("mgm"), nil, false)
+			dnsServer, err := NewDefaultServer(context.Background(), DefaultServerConfig{
+				WgInterface:    &mocWGIface{},
+				CustomAddress:  testCase.addrPort,
+				StatusRecorder: peer.NewRecorder("mgm"),
+				StateManager:   nil,
+				DisableSys:     false,
+			})
 			if err != nil {
 				t.Fatalf("%v", err)
 			}

client/internal/dns/upstream.go

@@ -26,10 +26,18 @@ import (
 	"github.com/netbirdio/netbird/client/proto"
 )
 
-const (
-	UpstreamTimeout = 15 * time.Second
+var currentMTU uint16 = iface.DefaultMTU
+
+func SetCurrentMTU(mtu uint16) {
+	currentMTU = mtu
+}
+
+const (
+	UpstreamTimeout = 4 * time.Second
+	// ClientTimeout is the timeout for the dns.Client.
+	// Set longer than UpstreamTimeout to ensure context timeout takes precedence
+	ClientTimeout = 5 * time.Second
 
-	failsTillDeact   = int32(5)
 	reactivatePeriod = 30 * time.Second
 	probeTimeout     = 2 * time.Second
 )
@@ -52,9 +60,7 @@ type upstreamResolverBase struct {
 	upstreamServers  []netip.AddrPort
 	domain           string
 	disabled         bool
-	failsCount       atomic.Int32
 	successCount     atomic.Int32
-	failsTillDeact   int32
 	mutex            sync.Mutex
 	reactivatePeriod time.Duration
 	upstreamTimeout  time.Duration
@@ -73,14 +79,13 @@ func newUpstreamResolverBase(ctx context.Context, statusRecorder *peer.Status, d
 		domain:           domain,
 		upstreamTimeout:  UpstreamTimeout,
 		reactivatePeriod: reactivatePeriod,
-		failsTillDeact:   failsTillDeact,
 		statusRecorder:   statusRecorder,
 	}
 }
 
 // String returns a string representation of the upstream resolver
 func (u *upstreamResolverBase) String() string {
-	return fmt.Sprintf("upstream %s", u.upstreamServers)
+	return fmt.Sprintf("Upstream %s", u.upstreamServers)
 }
 
 // ID returns the unique handler ID
@@ -110,58 +115,102 @@ func (u *upstreamResolverBase) Stop() {
 func (u *upstreamResolverBase) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	requestID := GenerateRequestID()
 	logger := log.WithField("request_id", requestID)
-	var err error
-	defer func() {
-		u.checkUpstreamFails(err)
-	}()
 
 	logger.Tracef("received upstream question: domain=%s type=%v class=%v", r.Question[0].Name, r.Question[0].Qtype, r.Question[0].Qclass)
+
+	u.prepareRequest(r)
+
+	if u.ctx.Err() != nil {
+		logger.Tracef("%s has been stopped", u)
+		return
+	}
+
+	if u.tryUpstreamServers(w, r, logger) {
+		return
+	}
+
+	u.writeErrorResponse(w, r, logger)
+}
+
+func (u *upstreamResolverBase) prepareRequest(r *dns.Msg) {
 	if r.Extra == nil {
 		r.MsgHdr.AuthenticatedData = true
 	}
+}
 
-	select {
-	case <-u.ctx.Done():
-		logger.Tracef("%s has been stopped", u)
-		return
-	default:
+func (u *upstreamResolverBase) tryUpstreamServers(w dns.ResponseWriter, r *dns.Msg, logger *log.Entry) bool {
+	timeout := u.upstreamTimeout
+	if len(u.upstreamServers) > 1 {
+		maxTotal := 5 * time.Second
+		minPerUpstream := 2 * time.Second
+		scaledTimeout := maxTotal / time.Duration(len(u.upstreamServers))
+		if scaledTimeout > minPerUpstream {
+			timeout = scaledTimeout
+		} else {
+			timeout = minPerUpstream
+		}
 	}
 
 	for _, upstream := range u.upstreamServers {
-		var rm *dns.Msg
-		var t time.Duration
-
-		func() {
-			ctx, cancel := context.WithTimeout(u.ctx, u.upstreamTimeout)
-			defer cancel()
-			rm, t, err = u.upstreamClient.exchange(ctx, upstream.String(), r)
-		}()
-
-		if err != nil {
-			if errors.Is(err, context.DeadlineExceeded) || isTimeout(err) {
-				logger.Warnf("upstream %s timed out for question domain=%s", upstream, r.Question[0].Name)
-				continue
-			}
-			logger.Warnf("failed to query upstream %s for question domain=%s: %s", upstream, r.Question[0].Name, err)
-			continue
+		if u.queryUpstream(w, r, upstream, timeout, logger) {
+			return true
 		}
+	}
+	return false
+}
 
-		if rm == nil || !rm.Response {
-			logger.Warnf("no response from upstream %s for question domain=%s", upstream, r.Question[0].Name)
-			continue
-		}
+func (u *upstreamResolverBase) queryUpstream(w dns.ResponseWriter, r *dns.Msg, upstream netip.AddrPort, timeout time.Duration, logger *log.Entry) bool {
+	var rm *dns.Msg
+	var t time.Duration
+	var err error
 
-		u.successCount.Add(1)
-		logger.Tracef("took %s to query the upstream %s for question domain=%s", t, upstream, r.Question[0].Name)
+	var startTime time.Time
+	func() {
+		ctx, cancel := context.WithTimeout(u.ctx, timeout)
+		defer cancel()
+		startTime = time.Now()
+		rm, t, err = u.upstreamClient.exchange(ctx, upstream.String(), r)
+	}()
 
-		if err = w.WriteMsg(rm); err != nil {
-			logger.Errorf("failed to write DNS response for question domain=%s: %s", r.Question[0].Name, err)
-		}
-		// count the fails only if they happen sequentially
-		u.failsCount.Store(0)
+	if err != nil {
+		u.handleUpstreamError(err, upstream, r.Question[0].Name, startTime, timeout, logger)
+		return false
+	}
+
+	if rm == nil || !rm.Response {
+		logger.Warnf("no response from upstream %s for question domain=%s", upstream, r.Question[0].Name)
+		return false
+	}
+
+	return u.writeSuccessResponse(w, rm, upstream, r.Question[0].Name, t, logger)
+}
+
+func (u *upstreamResolverBase) handleUpstreamError(err error, upstream netip.AddrPort, domain string, startTime time.Time, timeout time.Duration, logger *log.Entry) {
+	if !errors.Is(err, context.DeadlineExceeded) && !isTimeout(err) {
+		logger.Warnf("failed to query upstream %s for question domain=%s: %s", upstream, domain, err)
 		return
 	}
-	u.failsCount.Add(1)
+
+	elapsed := time.Since(startTime)
+	timeoutMsg := fmt.Sprintf("upstream %s timed out for question domain=%s after %v (timeout=%v)", upstream, domain, elapsed.Truncate(time.Millisecond), timeout)
+	if peerInfo := u.debugUpstreamTimeout(upstream); peerInfo != "" {
+		timeoutMsg += " " + peerInfo
+	}
+	timeoutMsg += fmt.Sprintf(" - error: %v", err)
+	logger.Warnf(timeoutMsg)
+}
+
+func (u *upstreamResolverBase) writeSuccessResponse(w dns.ResponseWriter, rm *dns.Msg, upstream netip.AddrPort, domain string, t time.Duration, logger *log.Entry) bool {
+	u.successCount.Add(1)
+	logger.Tracef("took %s to query the upstream %s for question domain=%s", t, upstream, domain)
+
+	if err := w.WriteMsg(rm); err != nil {
+		logger.Errorf("failed to write DNS response for question domain=%s: %s", domain, err)
+	}
+	return true
+}
+
+func (u *upstreamResolverBase) writeErrorResponse(w dns.ResponseWriter, r *dns.Msg, logger *log.Entry) {
 	logger.Errorf("all queries to the %s failed for question domain=%s", u, r.Question[0].Name)
 
 	m := new(dns.Msg)
@@ -171,41 +220,6 @@ func (u *upstreamResolverBase) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	}
 }
 
-// checkUpstreamFails counts fails and disables or enables upstream resolving
-//
-// If fails count is greater that failsTillDeact, upstream resolving
-// will be disabled for reactivatePeriod, after that time period fails counter
-// will be reset and upstream will be reactivated.
-func (u *upstreamResolverBase) checkUpstreamFails(err error) {
-	u.mutex.Lock()
-	defer u.mutex.Unlock()
-
-	if u.failsCount.Load() < u.failsTillDeact || u.disabled {
-		return
-	}
-
-	select {
-	case <-u.ctx.Done():
-		return
-	default:
-	}
-
-	u.disable(err)
-
-	if u.statusRecorder == nil {
-		return
-	}
-
-	u.statusRecorder.PublishEvent(
-		proto.SystemEvent_WARNING,
-		proto.SystemEvent_DNS,
-		"All upstream servers failed (fail count exceeded)",
-		"Unable to reach one or more DNS servers. This might affect your ability to connect to some services.",
-		map[string]string{"upstreams": u.upstreamServersString()},
-		// TODO add domain meta
-	)
-}
-
 // ProbeAvailability tests all upstream servers simultaneously and
 // disables the resolver if none work
 func (u *upstreamResolverBase) ProbeAvailability() {
@@ -218,8 +232,8 @@ func (u *upstreamResolverBase) ProbeAvailability() {
 	default:
 	}
 
-	// avoid probe if upstreams could resolve at least one query and fails count is less than failsTillDeact
-	if u.successCount.Load() > 0 && u.failsCount.Load() < u.failsTillDeact {
+	// avoid probe if upstreams could resolve at least one query
+	if u.successCount.Load() > 0 {
 		return
 	}
 
@@ -306,7 +320,6 @@ func (u *upstreamResolverBase) waitUntilResponse() {
 	}
 
 	log.Infof("upstreams %s are responsive again. Adding them back to system", u.upstreamServersString())
-	u.failsCount.Store(0)
 	u.successCount.Add(1)
 	u.reactivate()
 	u.disabled = false
@@ -358,8 +371,8 @@ func (u *upstreamResolverBase) testNameserver(server netip.AddrPort, timeout tim
 // If the passed context is nil, this will use Exchange instead of ExchangeContext.
 func ExchangeWithFallback(ctx context.Context, client *dns.Client, r *dns.Msg, upstream string) (*dns.Msg, time.Duration, error) {
 	// MTU - ip + udp headers
-	// Note: this could be sent out on an interface that is not ours, but our MTU should always be lower.
-	client.UDPSize = iface.DefaultMTU - (60 + 8)
+	// Note: this could be sent out on an interface that is not ours, but higher MTU settings could break truncation handling.
+	client.UDPSize = uint16(currentMTU - (60 + 8))
 
 	var (
 		rm  *dns.Msg
@@ -410,3 +423,80 @@ func GenerateRequestID() string {
 	}
 	return hex.EncodeToString(bytes)
 }
+
+// FormatPeerStatus formats peer connection status information for debugging DNS timeouts
+func FormatPeerStatus(peerState *peer.State) string {
+	isConnected := peerState.ConnStatus == peer.StatusConnected
+	hasRecentHandshake := !peerState.LastWireguardHandshake.IsZero() &&
+		time.Since(peerState.LastWireguardHandshake) < 3*time.Minute
+
+	statusInfo := fmt.Sprintf("%s:%s", peerState.FQDN, peerState.IP)
+
+	switch {
+	case !isConnected:
+		statusInfo += " DISCONNECTED"
+	case !hasRecentHandshake:
+		statusInfo += " NO_RECENT_HANDSHAKE"
+	default:
+		statusInfo += " connected"
+	}
+
+	if !peerState.LastWireguardHandshake.IsZero() {
+		timeSinceHandshake := time.Since(peerState.LastWireguardHandshake)
+		statusInfo += fmt.Sprintf(" last_handshake=%v_ago", timeSinceHandshake.Truncate(time.Second))
+	} else {
+		statusInfo += " no_handshake"
+	}
+
+	if peerState.Relayed {
+		statusInfo += " via_relay"
+	}
+
+	if peerState.Latency > 0 {
+		statusInfo += fmt.Sprintf(" latency=%v", peerState.Latency)
+	}
+
+	return statusInfo
+}
+
+// findPeerForIP finds which peer handles the given IP address
+func findPeerForIP(ip netip.Addr, statusRecorder *peer.Status) *peer.State {
+	if statusRecorder == nil {
+		return nil
+	}
+
+	fullStatus := statusRecorder.GetFullStatus()
+	var bestMatch *peer.State
+	var bestPrefixLen int
+
+	for _, peerState := range fullStatus.Peers {
+		routes := peerState.GetRoutes()
+		for route := range routes {
+			prefix, err := netip.ParsePrefix(route)
+			if err != nil {
+				continue
+			}
+
+			if prefix.Contains(ip) && prefix.Bits() > bestPrefixLen {
+				peerStateCopy := peerState
+				bestMatch = &peerStateCopy
+				bestPrefixLen = prefix.Bits()
+			}
+		}
+	}
+
+	return bestMatch
+}
+
+func (u *upstreamResolverBase) debugUpstreamTimeout(upstream netip.AddrPort) string {
+	if u.statusRecorder == nil {
+		return ""
+	}
+
+	peerInfo := findPeerForIP(upstream.Addr(), u.statusRecorder)
+	if peerInfo == nil {
+		return ""
+	}
+
+	return fmt.Sprintf("(routes through NetBird peer %s)", FormatPeerStatus(peerInfo))
+}

client/internal/dns/upstream_android.go

@@ -50,7 +50,9 @@ func (u *upstreamResolver) exchange(ctx context.Context, upstream string, r *dns
 }
 
 func (u *upstreamResolver) exchangeWithinVPN(ctx context.Context, upstream string, r *dns.Msg) (rm *dns.Msg, t time.Duration, err error) {
-	upstreamExchangeClient := &dns.Client{}
+	upstreamExchangeClient := &dns.Client{
+		Timeout: ClientTimeout,
+	}
 	return upstreamExchangeClient.ExchangeContext(ctx, r, upstream)
 }
 
@@ -72,10 +74,11 @@ func (u *upstreamResolver) exchangeWithoutVPN(ctx context.Context, upstream stri
 	}
 
 	upstreamExchangeClient := &dns.Client{
-		Dialer: dialer,
+		Dialer:  dialer,
+		Timeout: timeout,
 	}
 
-	return upstreamExchangeClient.Exchange(r, upstream)
+	return upstreamExchangeClient.ExchangeContext(ctx, r, upstream)
 }
 
 func (u *upstreamResolver) isLocalResolver(upstream string) bool {

client/internal/dns/upstream_general.go

@@ -34,7 +34,10 @@ func newUpstreamResolver(
 }
 
 func (u *upstreamResolver) exchange(ctx context.Context, upstream string, r *dns.Msg) (rm *dns.Msg, t time.Duration, err error) {
-	return ExchangeWithFallback(ctx, &dns.Client{}, r, upstream)
+	client := &dns.Client{
+		Timeout: ClientTimeout,
+	}
+	return ExchangeWithFallback(ctx, client, r, upstream)
 }
 
 func GetClientPrivate(ip netip.Addr, interfaceName string, dialTimeout time.Duration) (*dns.Client, error) {

client/internal/dns/upstream_ios.go

@@ -47,7 +47,9 @@ func newUpstreamResolver(
 }
 
 func (u *upstreamResolverIOS) exchange(ctx context.Context, upstream string, r *dns.Msg) (rm *dns.Msg, t time.Duration, err error) {
-	client := &dns.Client{}
+	client := &dns.Client{
+		Timeout: ClientTimeout,
+	}
 	upstreamHost, _, err := net.SplitHostPort(upstream)
 	if err != nil {
 		return nil, 0, fmt.Errorf("error while parsing upstream host: %s", err)
@@ -110,7 +112,8 @@ func GetClientPrivate(ip netip.Addr, interfaceName string, dialTimeout time.Dura
 		},
 	}
 	client := &dns.Client{
-		Dialer: dialer,
+		Dialer:  dialer,
+		Timeout: dialTimeout,
 	}
 	return client, nil
 }

client/internal/dns/upstream_test.go

@@ -124,29 +124,26 @@ func (c mockUpstreamResolver) exchange(_ context.Context, _ string, _ *dns.Msg)
 }
 
 func TestUpstreamResolver_DeactivationReactivation(t *testing.T) {
+	mockClient := &mockUpstreamResolver{
+		err: dns.ErrTime,
+		r:   new(dns.Msg),
+		rtt: time.Millisecond,
+	}
+
 	resolver := &upstreamResolverBase{
-		ctx: context.TODO(),
-		upstreamClient: &mockUpstreamResolver{
-			err: nil,
-			r:   new(dns.Msg),
-			rtt: time.Millisecond,
-		},
+		ctx:              context.TODO(),
+		upstreamClient:   mockClient,
 		upstreamTimeout:  UpstreamTimeout,
-		reactivatePeriod: reactivatePeriod,
-		failsTillDeact:   failsTillDeact,
+		reactivatePeriod: time.Microsecond * 100,
 	}
 	addrPort, _ := netip.ParseAddrPort("0.0.0.0:1") // Use valid port for parsing, test will still fail on connection
 	resolver.upstreamServers = []netip.AddrPort{netip.AddrPortFrom(addrPort.Addr().Unmap(), addrPort.Port())}
-	resolver.failsTillDeact = 0
-	resolver.reactivatePeriod = time.Microsecond * 100
-
-	responseWriter := &test.MockResponseWriter{
-		WriteMsgFunc: func(m *dns.Msg) error { return nil },
-	}
 
 	failed := false
 	resolver.deactivate = func(error) {
 		failed = true
+		// After deactivation, make the mock client work again
+		mockClient.err = nil
 	}
 
 	reactivated := false
@@ -154,7 +151,7 @@ func TestUpstreamResolver_DeactivationReactivation(t *testing.T) {
 		reactivated = true
 	}
 
-	resolver.ServeDNS(responseWriter, new(dns.Msg).SetQuestion("one.one.one.one.", dns.TypeA))
+	resolver.ProbeAvailability()
 
 	if !failed {
 		t.Errorf("expected that resolving was deactivated")
@@ -173,11 +170,6 @@ func TestUpstreamResolver_DeactivationReactivation(t *testing.T) {
 		return
 	}
 
-	if resolver.failsCount.Load() != 0 {
-		t.Errorf("fails count after reactivation should be 0")
-		return
-	}
-
 	if resolver.disabled {
 		t.Errorf("should be enabled")
 	}

client/internal/engine.go

@@ -7,6 +7,7 @@ import (
 	"math/rand"
 	"net"
 	"net/netip"
+	"net/url"
 	"os"
 	"reflect"
 	"runtime"
@@ -17,8 +18,8 @@ import (
 	"time"
 
 	"github.com/hashicorp/go-multierror"
-	"github.com/pion/ice/v3"
-	"github.com/pion/stun/v2"
+	"github.com/pion/ice/v4"
+	"github.com/pion/stun/v3"
 	log "github.com/sirupsen/logrus"
 	"golang.zx2c4.com/wireguard/tun/netstack"
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
@@ -33,6 +34,7 @@ import (
 	nbnetstack "github.com/netbirdio/netbird/client/iface/netstack"
 	"github.com/netbirdio/netbird/client/internal/acl"
 	"github.com/netbirdio/netbird/client/internal/dns"
+	dnsconfig "github.com/netbirdio/netbird/client/internal/dns/config"
 	"github.com/netbirdio/netbird/client/internal/dnsfwd"
 	"github.com/netbirdio/netbird/client/internal/ingressgw"
 	"github.com/netbirdio/netbird/client/internal/netflow"
@@ -55,11 +57,11 @@ import (
 	nbssh "github.com/netbirdio/netbird/client/ssh"
 	"github.com/netbirdio/netbird/client/system"
 	nbdns "github.com/netbirdio/netbird/dns"
+	"github.com/netbirdio/netbird/route"
 	mgm "github.com/netbirdio/netbird/shared/management/client"
 	mgmProto "github.com/netbirdio/netbird/shared/management/proto"
 	auth "github.com/netbirdio/netbird/shared/relay/auth/hmac"
 	relayClient "github.com/netbirdio/netbird/shared/relay/client"
-	"github.com/netbirdio/netbird/route"
 	signal "github.com/netbirdio/netbird/shared/signal/client"
 	sProto "github.com/netbirdio/netbird/shared/signal/proto"
 	"github.com/netbirdio/netbird/util"
@@ -125,6 +127,8 @@ type EngineConfig struct {
 	BlockInbound        bool
 
 	LazyConnectionEnabled bool
+
+	MTU uint16
 }
 
 // Engine is a mechanism responsible for reacting on Signal and Management stream events and managing connections to the remote peers.
@@ -254,6 +258,7 @@ func NewEngine(
 	}
 	engine.stateManager = statemanager.New(path)
 
+	log.Infof("I am: %s", config.WgPrivateKey.PublicKey().String())
 	return engine
 }
 
@@ -342,10 +347,14 @@ func (e *Engine) Stop() error {
 // Start creates a new WireGuard tunnel interface and listens to events from Signal and Management services
 // Connections to remote peers are not established here.
 // However, they will be established once an event with a list of peers to connect to will be received from Management Service
-func (e *Engine) Start() error {
+func (e *Engine) Start(netbirdConfig *mgmProto.NetbirdConfig, mgmtURL *url.URL) error {
 	e.syncMsgMux.Lock()
 	defer e.syncMsgMux.Unlock()
 
+	if err := iface.ValidateMTU(e.config.MTU); err != nil {
+		return fmt.Errorf("invalid MTU configuration: %w", err)
+	}
+
 	if e.cancel != nil {
 		e.cancel()
 	}
@@ -394,6 +403,11 @@ func (e *Engine) Start() error {
 	}
 	e.dnsServer = dnsServer
 
+	// Populate DNS cache with NetbirdConfig and management URL for early resolution
+	if err := e.PopulateNetbirdConfig(netbirdConfig, mgmtURL); err != nil {
+		log.Warnf("failed to populate DNS cache: %v", err)
+	}
+
 	e.routeManager = routemanager.NewManager(routemanager.ManagerConfig{
 		Context:             e.ctx,
 		PublicKey:           e.config.WgPrivateKey.PublicKey().String(),
@@ -654,6 +668,30 @@ func (e *Engine) removePeer(peerKey string) error {
 	return nil
 }
 
+// PopulateNetbirdConfig populates the DNS cache with infrastructure domains from login response
+func (e *Engine) PopulateNetbirdConfig(netbirdConfig *mgmProto.NetbirdConfig, mgmtURL *url.URL) error {
+	if e.dnsServer == nil {
+		return nil
+	}
+
+	// Populate management URL if provided
+	if mgmtURL != nil {
+		if err := e.dnsServer.PopulateManagementDomain(mgmtURL); err != nil {
+			log.Warnf("failed to populate DNS cache with management URL: %v", err)
+		}
+	}
+
+	// Populate NetbirdConfig domains if provided
+	if netbirdConfig != nil {
+		serverDomains := dnsconfig.ExtractFromNetbirdConfig(netbirdConfig)
+		if err := e.dnsServer.UpdateServerConfig(serverDomains); err != nil {
+			return fmt.Errorf("update DNS server config from NetbirdConfig: %w", err)
+		}
+	}
+
+	return nil
+}
+
 func (e *Engine) handleSync(update *mgmProto.SyncResponse) error {
 	e.syncMsgMux.Lock()
 	defer e.syncMsgMux.Unlock()
@@ -685,6 +723,10 @@ func (e *Engine) handleSync(update *mgmProto.SyncResponse) error {
 			return fmt.Errorf("handle the flow configuration: %w", err)
 		}
 
+		if err := e.PopulateNetbirdConfig(wCfg, nil); err != nil {
+			log.Warnf("Failed to update DNS server config: %v", err)
+		}
+
 		// todo update signal
 	}
 
@@ -1110,15 +1152,16 @@ func toRoutes(protoRoutes []*mgmProto.Route) []*route.Route {
 		}
 
 		convertedRoute := &route.Route{
-			ID:          route.ID(protoRoute.ID),
-			Network:     prefix.Masked(),
-			Domains:     domain.FromPunycodeList(protoRoute.Domains),
-			NetID:       route.NetID(protoRoute.NetID),
-			NetworkType: route.NetworkType(protoRoute.NetworkType),
-			Peer:        protoRoute.Peer,
-			Metric:      int(protoRoute.Metric),
-			Masquerade:  protoRoute.Masquerade,
-			KeepRoute:   protoRoute.KeepRoute,
+			ID:            route.ID(protoRoute.ID),
+			Network:       prefix.Masked(),
+			Domains:       domain.FromPunycodeList(protoRoute.Domains),
+			NetID:         route.NetID(protoRoute.NetID),
+			NetworkType:   route.NetworkType(protoRoute.NetworkType),
+			Peer:          protoRoute.Peer,
+			Metric:        int(protoRoute.Metric),
+			Masquerade:    protoRoute.Masquerade,
+			KeepRoute:     protoRoute.KeepRoute,
+			SkipAutoApply: protoRoute.SkipAutoApply,
 		}
 		routes = append(routes, convertedRoute)
 	}
@@ -1330,52 +1373,17 @@ func (e *Engine) receiveSignalEvents() {
 			}
 
 			switch msg.GetBody().Type {
-			case sProto.Body_OFFER:
-				remoteCred, err := signal.UnMarshalCredential(msg)
+			case sProto.Body_OFFER, sProto.Body_ANSWER:
+				offerAnswer, err := convertToOfferAnswer(msg)
 				if err != nil {
 					return err
 				}
 
-				var rosenpassPubKey []byte
-				rosenpassAddr := ""
-				if msg.GetBody().GetRosenpassConfig() != nil {
-					rosenpassPubKey = msg.GetBody().GetRosenpassConfig().GetRosenpassPubKey()
-					rosenpassAddr = msg.GetBody().GetRosenpassConfig().GetRosenpassServerAddr()
+				if msg.Body.Type == sProto.Body_OFFER {
+					conn.OnRemoteOffer(*offerAnswer)
+				} else {
+					conn.OnRemoteAnswer(*offerAnswer)
 				}
-				conn.OnRemoteOffer(peer.OfferAnswer{
-					IceCredentials: peer.IceCredentials{
-						UFrag: remoteCred.UFrag,
-						Pwd:   remoteCred.Pwd,
-					},
-					WgListenPort:    int(msg.GetBody().GetWgListenPort()),
-					Version:         msg.GetBody().GetNetBirdVersion(),
-					RosenpassPubKey: rosenpassPubKey,
-					RosenpassAddr:   rosenpassAddr,
-					RelaySrvAddress: msg.GetBody().GetRelayServerAddress(),
-				})
-			case sProto.Body_ANSWER:
-				remoteCred, err := signal.UnMarshalCredential(msg)
-				if err != nil {
-					return err
-				}
-
-				var rosenpassPubKey []byte
-				rosenpassAddr := ""
-				if msg.GetBody().GetRosenpassConfig() != nil {
-					rosenpassPubKey = msg.GetBody().GetRosenpassConfig().GetRosenpassPubKey()
-					rosenpassAddr = msg.GetBody().GetRosenpassConfig().GetRosenpassServerAddr()
-				}
-				conn.OnRemoteAnswer(peer.OfferAnswer{
-					IceCredentials: peer.IceCredentials{
-						UFrag: remoteCred.UFrag,
-						Pwd:   remoteCred.Pwd,
-					},
-					WgListenPort:    int(msg.GetBody().GetWgListenPort()),
-					Version:         msg.GetBody().GetNetBirdVersion(),
-					RosenpassPubKey: rosenpassPubKey,
-					RosenpassAddr:   rosenpassAddr,
-					RelaySrvAddress: msg.GetBody().GetRelayServerAddress(),
-				})
 			case sProto.Body_CANDIDATE:
 				candidate, err := ice.UnmarshalCandidate(msg.GetBody().Payload)
 				if err != nil {
@@ -1525,7 +1533,7 @@ func (e *Engine) newWgIface() (*iface.WGIface, error) {
 		Address:      e.config.WgAddr,
 		WGPort:       e.config.WgPort,
 		WGPrivKey:    e.config.WgPrivateKey.String(),
-		MTU:          iface.DefaultMTU,
+		MTU:          e.config.MTU,
 		TransportNet: transportNet,
 		FilterFn:     e.addrViaRoutes,
 		DisableDNS:   e.config.DisableDNS,
@@ -1584,7 +1592,14 @@ func (e *Engine) newDnsServer(dnsConfig *nbdns.Config) (dns.Server, error) {
 		return dnsServer, nil
 
 	default:
-		dnsServer, err := dns.NewDefaultServer(e.ctx, e.wgInterface, e.config.CustomDNSAddress, e.statusRecorder, e.stateManager, e.config.DisableDNS)
+
+		dnsServer, err := dns.NewDefaultServer(e.ctx, dns.DefaultServerConfig{
+			WgInterface:    e.wgInterface,
+			CustomAddress:  e.config.CustomDNSAddress,
+			StatusRecorder: e.statusRecorder,
+			StateManager:   e.stateManager,
+			DisableSys:     e.config.DisableDNS,
+		})
 		if err != nil {
 			return nil, err
 		}
@@ -2073,3 +2088,44 @@ func createFile(path string) error {
 	}
 	return file.Close()
 }
+
+func convertToOfferAnswer(msg *sProto.Message) (*peer.OfferAnswer, error) {
+	remoteCred, err := signal.UnMarshalCredential(msg)
+	if err != nil {
+		return nil, err
+	}
+
+	var (
+		rosenpassPubKey []byte
+		rosenpassAddr   string
+	)
+	if cfg := msg.GetBody().GetRosenpassConfig(); cfg != nil {
+		rosenpassPubKey = cfg.GetRosenpassPubKey()
+		rosenpassAddr = cfg.GetRosenpassServerAddr()
+	}
+
+	// Handle optional SessionID
+	var sessionID *peer.ICESessionID
+	if sessionBytes := msg.GetBody().GetSessionId(); sessionBytes != nil {
+		if id, err := peer.ICESessionIDFromBytes(sessionBytes); err != nil {
+			log.Warnf("Invalid session ID in message: %v", err)
+			sessionID = nil // Set to nil if conversion fails
+		} else {
+			sessionID = &id
+		}
+	}
+
+	offerAnswer := peer.OfferAnswer{
+		IceCredentials: peer.IceCredentials{
+			UFrag: remoteCred.UFrag,
+			Pwd:   remoteCred.Pwd,
+		},
+		WgListenPort:    int(msg.GetBody().GetWgListenPort()),
+		Version:         msg.GetBody().GetNetBirdVersion(),
+		RosenpassPubKey: rosenpassPubKey,
+		RosenpassAddr:   rosenpassAddr,
+		RelaySrvAddress: msg.GetBody().GetRelayServerAddress(),
+		SessionID:       sessionID,
+	}
+	return &offerAnswer, nil
+}

client/internal/engine_test.go

@@ -19,15 +19,13 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"go.opentelemetry.io/otel"
+	wgdevice "golang.zx2c4.com/wireguard/device"
+	"golang.zx2c4.com/wireguard/tun/netstack"
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/keepalive"
 
-	wgdevice "golang.zx2c4.com/wireguard/device"
-	"golang.zx2c4.com/wireguard/tun/netstack"
-
 	"github.com/netbirdio/management-integrations/integrations"
-
 	"github.com/netbirdio/netbird/client/iface"
 	"github.com/netbirdio/netbird/client/iface/bind"
 	"github.com/netbirdio/netbird/client/iface/configurer"
@@ -43,19 +41,22 @@ import (
 	"github.com/netbirdio/netbird/client/ssh"
 	"github.com/netbirdio/netbird/client/system"
 	nbdns "github.com/netbirdio/netbird/dns"
-	mgmt "github.com/netbirdio/netbird/shared/management/client"
-	mgmtProto "github.com/netbirdio/netbird/shared/management/proto"
+	"github.com/netbirdio/netbird/management/internals/server/config"
 	"github.com/netbirdio/netbird/management/server"
 	"github.com/netbirdio/netbird/management/server/activity"
+	"github.com/netbirdio/netbird/management/server/groups"
 	"github.com/netbirdio/netbird/management/server/integrations/port_forwarding"
+	"github.com/netbirdio/netbird/management/server/peers"
 	"github.com/netbirdio/netbird/management/server/permissions"
 	"github.com/netbirdio/netbird/management/server/settings"
 	"github.com/netbirdio/netbird/management/server/store"
 	"github.com/netbirdio/netbird/management/server/telemetry"
 	"github.com/netbirdio/netbird/management/server/types"
 	"github.com/netbirdio/netbird/monotime"
-	relayClient "github.com/netbirdio/netbird/shared/relay/client"
 	"github.com/netbirdio/netbird/route"
+	mgmt "github.com/netbirdio/netbird/shared/management/client"
+	mgmtProto "github.com/netbirdio/netbird/shared/management/proto"
+	relayClient "github.com/netbirdio/netbird/shared/relay/client"
 	signal "github.com/netbirdio/netbird/shared/signal/client"
 	"github.com/netbirdio/netbird/shared/signal/proto"
 	signalServer "github.com/netbirdio/netbird/signal/server"
@@ -216,7 +217,7 @@ func TestEngine_SSH(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String())
+	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String(), iface.DefaultMTU)
 	engine := NewEngine(
 		ctx, cancel,
 		&signal.MockClient{},
@@ -228,6 +229,7 @@ func TestEngine_SSH(t *testing.T) {
 			WgPrivateKey:     key,
 			WgPort:           33100,
 			ServerSSHAllowed: true,
+			MTU:              iface.DefaultMTU,
 		},
 		MobileDependency{},
 		peer.NewRecorder("https://mgm"),
@@ -263,7 +265,7 @@ func TestEngine_SSH(t *testing.T) {
 			},
 		}, nil
 	}
-	err = engine.Start()
+	err = engine.Start(nil, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -361,7 +363,7 @@ func TestEngine_UpdateNetworkMap(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String())
+	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String(), iface.DefaultMTU)
 	engine := NewEngine(
 		ctx, cancel,
 		&signal.MockClient{},
@@ -372,6 +374,7 @@ func TestEngine_UpdateNetworkMap(t *testing.T) {
 			WgAddr:       "100.64.0.1/24",
 			WgPrivateKey: key,
 			WgPort:       33100,
+			MTU:          iface.DefaultMTU,
 		},
 		MobileDependency{},
 		peer.NewRecorder("https://mgm"),
@@ -410,7 +413,7 @@ func TestEngine_UpdateNetworkMap(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	engine.udpMux = bind.NewUniversalUDPMuxDefault(bind.UniversalUDPMuxParams{UDPConn: conn})
+	engine.udpMux = bind.NewUniversalUDPMuxDefault(bind.UniversalUDPMuxParams{UDPConn: conn, MTU: 1280})
 	engine.ctx = ctx
 	engine.srWatcher = guard.NewSRWatcher(nil, nil, nil, icemaker.Config{})
 	engine.connMgr = NewConnMgr(engine.config, engine.statusRecorder, engine.peerStore, wgIface)
@@ -587,12 +590,13 @@ func TestEngine_Sync(t *testing.T) {
 		}
 		return nil
 	}
-	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String())
+	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String(), iface.DefaultMTU)
 	engine := NewEngine(ctx, cancel, &signal.MockClient{}, &mgmt.MockClient{SyncFunc: syncFunc}, relayMgr, &EngineConfig{
 		WgIfaceName:  "utun103",
 		WgAddr:       "100.64.0.1/24",
 		WgPrivateKey: key,
 		WgPort:       33100,
+		MTU:          iface.DefaultMTU,
 	}, MobileDependency{}, peer.NewRecorder("https://mgm"), nil)
 	engine.ctx = ctx
 
@@ -607,7 +611,7 @@ func TestEngine_Sync(t *testing.T) {
 		}
 	}()
 
-	err = engine.Start()
+	err = engine.Start(nil, nil)
 	if err != nil {
 		t.Fatal(err)
 		return
@@ -751,12 +755,13 @@ func TestEngine_UpdateNetworkMapWithRoutes(t *testing.T) {
 			wgIfaceName := fmt.Sprintf("utun%d", 104+n)
 			wgAddr := fmt.Sprintf("100.66.%d.1/24", n)
 
-			relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String())
+			relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String(), iface.DefaultMTU)
 			engine := NewEngine(ctx, cancel, &signal.MockClient{}, &mgmt.MockClient{}, relayMgr, &EngineConfig{
 				WgIfaceName:  wgIfaceName,
 				WgAddr:       wgAddr,
 				WgPrivateKey: key,
 				WgPort:       33100,
+				MTU:          iface.DefaultMTU,
 			}, MobileDependency{}, peer.NewRecorder("https://mgm"), nil)
 			engine.ctx = ctx
 			newNet, err := stdnet.NewNet()
@@ -952,12 +957,13 @@ func TestEngine_UpdateNetworkMapWithDNSUpdate(t *testing.T) {
 			wgIfaceName := fmt.Sprintf("utun%d", 104+n)
 			wgAddr := fmt.Sprintf("100.66.%d.1/24", n)
 
-			relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String())
+			relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String(), iface.DefaultMTU)
 			engine := NewEngine(ctx, cancel, &signal.MockClient{}, &mgmt.MockClient{}, relayMgr, &EngineConfig{
 				WgIfaceName:  wgIfaceName,
 				WgAddr:       wgAddr,
 				WgPrivateKey: key,
 				WgPort:       33100,
+				MTU:          iface.DefaultMTU,
 			}, MobileDependency{}, peer.NewRecorder("https://mgm"), nil)
 			engine.ctx = ctx
 
@@ -1062,7 +1068,7 @@ func TestEngine_MultiplePeers(t *testing.T) {
 			defer mu.Unlock()
 			guid := fmt.Sprintf("{%s}", uuid.New().String())
 			device.CustomWindowsGUIDString = strings.ToLower(guid)
-			err = engine.Start()
+			err = engine.Start(nil, nil)
 			if err != nil {
 				t.Errorf("unable to start engine for peer %d with error %v", j, err)
 				wg.Done()
@@ -1179,6 +1185,7 @@ func Test_ParseNATExternalIPMappings(t *testing.T) {
 				config: &EngineConfig{
 					IFaceBlackList: testCase.inputBlacklistInterface,
 					NATExternalIPs: testCase.inputMapList,
+					MTU:            iface.DefaultMTU,
 				},
 			}
 			parsedList := engine.parseNATExternalIPMappings()
@@ -1479,9 +1486,10 @@ func createEngine(ctx context.Context, cancel context.CancelFunc, setupKey strin
 		WgAddr:       resp.PeerConfig.Address,
 		WgPrivateKey: key,
 		WgPort:       wgPort,
+		MTU:          iface.DefaultMTU,
 	}
 
-	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String())
+	relayMgr := relayClient.NewManager(ctx, nil, key.PublicKey().String(), iface.DefaultMTU)
 	e, err := NewEngine(ctx, cancel, signalClient, mgmtClient, relayMgr, conf, MobileDependency{}, peer.NewRecorder("https://mgm"), nil), nil
 	e.ctx = ctx
 	return e, err
@@ -1513,15 +1521,15 @@ func startSignal(t *testing.T) (*grpc.Server, string, error) {
 func startManagement(t *testing.T, dataDir, testFile string) (*grpc.Server, string, error) {
 	t.Helper()
 
-	config := &types.Config{
-		Stuns:      []*types.Host{},
-		TURNConfig: &types.TURNConfig{},
-		Relay: &types.Relay{
+	config := &config.Config{
+		Stuns:      []*config.Host{},
+		TURNConfig: &config.TURNConfig{},
+		Relay: &config.Relay{
 			Addresses:      []string{"127.0.0.1:1234"},
 			CredentialsTTL: util.Duration{Duration: time.Hour},
 			Secret:         "222222222222222222",
 		},
-		Signal: &types.Host{
+		Signal: &config.Host{
 			Proto: "http",
 			URI:   "localhost:10000",
 		},
@@ -1546,7 +1554,10 @@ func startManagement(t *testing.T, dataDir, testFile string) (*grpc.Server, stri
 	if err != nil {
 		return nil, "", err
 	}
-	ia, _ := integrations.NewIntegratedValidator(context.Background(), eventStore)
+
+	permissionsManager := permissions.NewManager(store)
+	peersManager := peers.NewManager(store, permissionsManager)
+	ia, _ := integrations.NewIntegratedValidator(context.Background(), peersManager, eventStore)
 
 	metrics, err := telemetry.NewDefaultAppMetrics(context.Background())
 	require.NoError(t, err)
@@ -1563,14 +1574,14 @@ func startManagement(t *testing.T, dataDir, testFile string) (*grpc.Server, stri
 		Return(&types.ExtraSettings{}, nil).
 		AnyTimes()
 
-	permissionsManager := permissions.NewManager(store)
+	groupsManager := groups.NewManagerMock()
 
 	accountManager, err := server.BuildManager(context.Background(), store, peersUpdateManager, nil, "", "netbird.selfhosted", eventStore, nil, false, ia, metrics, port_forwarding.NewControllerMock(), settingsMockManager, permissionsManager, false)
 	if err != nil {
 		return nil, "", err
 	}
 
-	secretsManager := server.NewTimeBasedAuthSecretsManager(peersUpdateManager, config.TURNConfig, config.Relay, settingsMockManager)
+	secretsManager := server.NewTimeBasedAuthSecretsManager(peersUpdateManager, config.TURNConfig, config.Relay, settingsMockManager, groupsManager)
 	mgmtServer, err := server.NewServer(context.Background(), config, accountManager, settingsMockManager, peersUpdateManager, secretsManager, nil, nil, nil, &server.MockIntegratedValidator{})
 	if err != nil {
 		return nil, "", err

client/internal/login.go

@@ -40,7 +40,7 @@ func IsLoginRequired(ctx context.Context, config *profilemanager.Config) (bool,
 		return false, err
 	}
 
-	_, err = doMgmLogin(ctx, mgmClient, pubSSHKey, config)
+	_, _, err = doMgmLogin(ctx, mgmClient, pubSSHKey, config)
 	if isLoginNeeded(err) {
 		return true, nil
 	}
@@ -69,14 +69,18 @@ func Login(ctx context.Context, config *profilemanager.Config, setupKey string,
 		return err
 	}
 
-	serverKey, err := doMgmLogin(ctx, mgmClient, pubSSHKey, config)
+	serverKey, _, err := doMgmLogin(ctx, mgmClient, pubSSHKey, config)
 	if serverKey != nil && isRegistrationNeeded(err) {
 		log.Debugf("peer registration required")
 		_, err = registerPeer(ctx, *serverKey, mgmClient, setupKey, jwtToken, pubSSHKey, config)
+		if err != nil {
+			return err
+		}
+	} else if err != nil {
 		return err
 	}
 
-	return err
+	return nil
 }
 
 func getMgmClient(ctx context.Context, privateKey string, mgmURL *url.URL) (*mgm.GrpcClient, error) {
@@ -101,11 +105,11 @@ func getMgmClient(ctx context.Context, privateKey string, mgmURL *url.URL) (*mgm
 	return mgmClient, err
 }
 
-func doMgmLogin(ctx context.Context, mgmClient *mgm.GrpcClient, pubSSHKey []byte, config *profilemanager.Config) (*wgtypes.Key, error) {
+func doMgmLogin(ctx context.Context, mgmClient *mgm.GrpcClient, pubSSHKey []byte, config *profilemanager.Config) (*wgtypes.Key, *mgmProto.LoginResponse, error) {
 	serverKey, err := mgmClient.GetServerPublicKey()
 	if err != nil {
 		log.Errorf("failed while getting Management Service public key: %v", err)
-		return nil, err
+		return nil, nil, err
 	}
 
 	sysInfo := system.GetInfo(ctx)
@@ -121,8 +125,8 @@ func doMgmLogin(ctx context.Context, mgmClient *mgm.GrpcClient, pubSSHKey []byte
 		config.BlockInbound,
 		config.LazyConnectionEnabled,
 	)
-	_, err = mgmClient.Login(*serverKey, sysInfo, pubSSHKey, config.DNSLabels)
-	return serverKey, err
+	loginResp, err := mgmClient.Login(*serverKey, sysInfo, pubSSHKey, config.DNSLabels)
+	return serverKey, loginResp, err
 }
 
 // registerPeer checks whether setupKey was provided via cmd line and if not then it prompts user to enter a key.

client/internal/peer/conn.go

@@ -11,7 +11,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/pion/ice/v3"
+	"github.com/pion/ice/v4"
 	log "github.com/sirupsen/logrus"
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 
@@ -24,8 +24,8 @@ import (
 	"github.com/netbirdio/netbird/client/internal/peer/id"
 	"github.com/netbirdio/netbird/client/internal/peer/worker"
 	"github.com/netbirdio/netbird/client/internal/stdnet"
-	relayClient "github.com/netbirdio/netbird/shared/relay/client"
 	"github.com/netbirdio/netbird/route"
+	relayClient "github.com/netbirdio/netbird/shared/relay/client"
 	semaphoregroup "github.com/netbirdio/netbird/util/semaphore-group"
 )
 
@@ -200,19 +200,11 @@ func (conn *Conn) Open(engineCtx context.Context) error {
 	conn.wg.Add(1)
 	go func() {
 		defer conn.wg.Done()
+
 		conn.waitInitialRandomSleepTime(conn.ctx)
 		conn.semaphore.Done(conn.ctx)
 
-		conn.dumpState.SendOffer()
-		if err := conn.handshaker.sendOffer(); err != nil {
-			conn.Log.Errorf("failed to send initial offer: %v", err)
-		}
-
-		conn.wg.Add(1)
-		go func() {
-			conn.guard.Start(conn.ctx, conn.onGuardEvent)
-			conn.wg.Done()
-		}()
+		conn.guard.Start(conn.ctx, conn.onGuardEvent)
 	}()
 	conn.opened = true
 	return nil
@@ -274,10 +266,10 @@ func (conn *Conn) Close(signalToRemote bool) {
 
 // OnRemoteAnswer handles an offer from the remote peer and returns true if the message was accepted, false otherwise
 // doesn't block, discards the message if connection wasn't ready
-func (conn *Conn) OnRemoteAnswer(answer OfferAnswer) bool {
+func (conn *Conn) OnRemoteAnswer(answer OfferAnswer) {
 	conn.dumpState.RemoteAnswer()
 	conn.Log.Infof("OnRemoteAnswer, priority: %s, status ICE: %s, status relay: %s", conn.currentConnPriority, conn.statusICE, conn.statusRelay)
-	return conn.handshaker.OnRemoteAnswer(answer)
+	conn.handshaker.OnRemoteAnswer(answer)
 }
 
 // OnRemoteCandidate Handles ICE connection Candidate provided by the remote peer.
@@ -296,10 +288,10 @@ func (conn *Conn) SetOnDisconnected(handler func(remotePeer string)) {
 	conn.onDisconnected = handler
 }
 
-func (conn *Conn) OnRemoteOffer(offer OfferAnswer) bool {
+func (conn *Conn) OnRemoteOffer(offer OfferAnswer) {
 	conn.dumpState.RemoteOffer()
 	conn.Log.Infof("OnRemoteOffer, on status ICE: %s, status Relay: %s", conn.statusICE, conn.statusRelay)
-	return conn.handshaker.OnRemoteOffer(offer)
+	conn.handshaker.OnRemoteOffer(offer)
 }
 
 // WgConfig returns the WireGuard config
@@ -548,7 +540,6 @@ func (conn *Conn) onRelayDisconnected() {
 }
 
 func (conn *Conn) onGuardEvent() {
-	conn.Log.Debugf("send offer to peer")
 	conn.dumpState.SendOffer()
 	if err := conn.handshaker.SendOffer(); err != nil {
 		conn.Log.Errorf("failed to send offer: %v", err)
@@ -672,7 +663,7 @@ func (conn *Conn) isConnectedOnAllWay() (connected bool) {
 		}
 	}()
 
-	if conn.statusICE.Get() == worker.StatusDisconnected {
+	if conn.statusICE.Get() == worker.StatusDisconnected && !conn.workerICE.InProgress() {
 		return false
 	}
 

client/internal/peer/conn_test.go

@@ -1,9 +1,9 @@
 package peer
 
 import (
+	"context"
 	"fmt"
 	"os"
-	"sync"
 	"testing"
 	"time"
 
@@ -79,31 +79,30 @@ func TestConn_OnRemoteOffer(t *testing.T) {
 		return
 	}
 
-	wg := sync.WaitGroup{}
-	wg.Add(2)
-	go func() {
-		<-conn.handshaker.remoteOffersCh
-		wg.Done()
-	}()
+	onNewOffeChan := make(chan struct{})
 
-	go func() {
-		for {
-			accepted := conn.OnRemoteOffer(OfferAnswer{
-				IceCredentials: IceCredentials{
-					UFrag: "test",
-					Pwd:   "test",
-				},
-				WgListenPort: 0,
-				Version:      "",
-			})
-			if accepted {
-				wg.Done()
-				return
-			}
-		}
-	}()
+	conn.handshaker.AddOnNewOfferListener(func(remoteOfferAnswer *OfferAnswer) {
+		onNewOffeChan <- struct{}{}
+	})
 
-	wg.Wait()
+	conn.OnRemoteOffer(OfferAnswer{
+		IceCredentials: IceCredentials{
+			UFrag: "test",
+			Pwd:   "test",
+		},
+		WgListenPort: 0,
+		Version:      "",
+	})
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	select {
+	case <-onNewOffeChan:
+		// success
+	case <-ctx.Done():
+		t.Error("expected to receive a new offer notification, but timed out")
+	}
 }
 
 func TestConn_OnRemoteAnswer(t *testing.T) {
@@ -119,31 +118,29 @@ func TestConn_OnRemoteAnswer(t *testing.T) {
 		return
 	}
 
-	wg := sync.WaitGroup{}
-	wg.Add(2)
-	go func() {
-		<-conn.handshaker.remoteAnswerCh
-		wg.Done()
-	}()
+	onNewOffeChan := make(chan struct{})
 
-	go func() {
-		for {
-			accepted := conn.OnRemoteAnswer(OfferAnswer{
-				IceCredentials: IceCredentials{
-					UFrag: "test",
-					Pwd:   "test",
-				},
-				WgListenPort: 0,
-				Version:      "",
-			})
-			if accepted {
-				wg.Done()
-				return
-			}
-		}
-	}()
+	conn.handshaker.AddOnNewOfferListener(func(remoteOfferAnswer *OfferAnswer) {
+		onNewOffeChan <- struct{}{}
+	})
 
-	wg.Wait()
+	conn.OnRemoteAnswer(OfferAnswer{
+		IceCredentials: IceCredentials{
+			UFrag: "test",
+			Pwd:   "test",
+		},
+		WgListenPort: 0,
+		Version:      "",
+	})
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	select {
+	case <-onNewOffeChan:
+		// success
+	case <-ctx.Done():
+		t.Error("expected to receive a new offer notification, but timed out")
+	}
 }
 
 func TestConn_presharedKey(t *testing.T) {

client/internal/peer/guard/guard.go

@@ -19,7 +19,6 @@ type isConnectedFunc func() bool
 // - Relayed connection disconnected
 // - ICE candidate changes
 type Guard struct {
-	Reconnect               chan struct{}
 	log                     *log.Entry
 	isConnectedOnAllWay     isConnectedFunc
 	timeout                 time.Duration
@@ -30,7 +29,6 @@ type Guard struct {
 
 func NewGuard(log *log.Entry, isConnectedFn isConnectedFunc, timeout time.Duration, srWatcher *SRWatcher) *Guard {
 	return &Guard{
-		Reconnect:               make(chan struct{}, 1),
 		log:                     log,
 		isConnectedOnAllWay:     isConnectedFn,
 		timeout:                 timeout,
@@ -41,6 +39,7 @@ func NewGuard(log *log.Entry, isConnectedFn isConnectedFunc, timeout time.Durati
 }
 
 func (g *Guard) Start(ctx context.Context, eventCallback func()) {
+	g.log.Infof("starting guard for reconnection with MaxInterval: %s", g.timeout)
 	g.reconnectLoopWithRetry(ctx, eventCallback)
 }
 
@@ -61,17 +60,14 @@ func (g *Guard) SetICEConnDisconnected() {
 // reconnectLoopWithRetry periodically check the connection status.
 // Try to send offer while the P2P is not established or while the Relay is not connected if is it supported
 func (g *Guard) reconnectLoopWithRetry(ctx context.Context, callback func()) {
-	waitForInitialConnectionTry(ctx)
-
 	srReconnectedChan := g.srWatcher.NewListener()
 	defer g.srWatcher.RemoveListener(srReconnectedChan)
 
-	ticker := g.prepareExponentTicker(ctx)
+	ticker := g.initialTicker(ctx)
 	defer ticker.Stop()
 
 	tickerChannel := ticker.C
 
-	g.log.Infof("start reconnect loop...")
 	for {
 		select {
 		case t := <-tickerChannel:
@@ -85,7 +81,6 @@ func (g *Guard) reconnectLoopWithRetry(ctx context.Context, callback func()) {
 			if !g.isConnectedOnAllWay() {
 				callback()
 			}
-
 		case <-g.relayedConnDisconnected:
 			g.log.Debugf("Relay connection changed, reset reconnection ticker")
 			ticker.Stop()
@@ -111,6 +106,20 @@ func (g *Guard) reconnectLoopWithRetry(ctx context.Context, callback func()) {
 	}
 }
 
+// initialTicker give chance to the peer to establish the initial connection.
+func (g *Guard) initialTicker(ctx context.Context) *backoff.Ticker {
+	bo := backoff.WithContext(&backoff.ExponentialBackOff{
+		InitialInterval:     3 * time.Second,
+		RandomizationFactor: 0.1,
+		Multiplier:          2,
+		MaxInterval:         g.timeout,
+		Stop:                backoff.Stop,
+		Clock:               backoff.SystemClock,
+	}, ctx)
+
+	return backoff.NewTicker(bo)
+}
+
 func (g *Guard) prepareExponentTicker(ctx context.Context) *backoff.Ticker {
 	bo := backoff.WithContext(&backoff.ExponentialBackOff{
 		InitialInterval:     800 * time.Millisecond,
@@ -126,13 +135,3 @@ func (g *Guard) prepareExponentTicker(ctx context.Context) *backoff.Ticker {
 
 	return ticker
 }
-
-// Give chance to the peer to establish the initial connection.
-// With it, we can decrease to send necessary offer
-func waitForInitialConnectionTry(ctx context.Context) {
-	select {
-	case <-ctx.Done():
-		return
-	case <-time.After(3 * time.Second):
-	}
-}

client/internal/peer/guard/ice_monitor.go

@@ -6,7 +6,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/pion/ice/v3"
+	"github.com/pion/ice/v4"
 	log "github.com/sirupsen/logrus"
 
 	icemaker "github.com/netbirdio/netbird/client/internal/peer/ice"

client/internal/peer/handshaker.go

@@ -39,6 +39,15 @@ type OfferAnswer struct {
 
 	// relay server address
 	RelaySrvAddress string
+	// SessionID is the unique identifier of the session, used to discard old messages
+	SessionID *ICESessionID
+}
+
+func (oa *OfferAnswer) SessionIDString() string {
+	if oa.SessionID == nil {
+		return "unknown"
+	}
+	return oa.SessionID.String()
 }
 
 type Handshaker struct {
@@ -74,21 +83,25 @@ func (h *Handshaker) AddOnNewOfferListener(offer func(remoteOfferAnswer *OfferAn
 
 func (h *Handshaker) Listen(ctx context.Context) {
 	for {
-		h.log.Info("wait for remote offer confirmation")
-		remoteOfferAnswer, err := h.waitForRemoteOfferConfirmation(ctx)
-		if err != nil {
-			var connectionClosedError *ConnectionClosedError
-			if errors.As(err, &connectionClosedError) {
-				h.log.Info("exit from handshaker")
-				return
+		select {
+		case remoteOfferAnswer := <-h.remoteOffersCh:
+			// received confirmation from the remote peer -> ready to proceed
+			if err := h.sendAnswer(); err != nil {
+				h.log.Errorf("failed to send remote offer confirmation: %s", err)
+				continue
 			}
-			h.log.Errorf("failed to received remote offer confirmation: %s", err)
-			continue
-		}
-
-		h.log.Infof("received connection confirmation, running version %s and with remote WireGuard listen port %d", remoteOfferAnswer.Version, remoteOfferAnswer.WgListenPort)
-		for _, listener := range h.onNewOfferListeners {
-			go listener(remoteOfferAnswer)
+			for _, listener := range h.onNewOfferListeners {
+				listener(&remoteOfferAnswer)
+			}
+			h.log.Infof("received offer, running version %s, remote WireGuard listen port %d, session id: %s", remoteOfferAnswer.Version, remoteOfferAnswer.WgListenPort, remoteOfferAnswer.SessionIDString())
+		case remoteOfferAnswer := <-h.remoteAnswerCh:
+			h.log.Infof("received answer, running version %s, remote WireGuard listen port %d, session id: %s", remoteOfferAnswer.Version, remoteOfferAnswer.WgListenPort, remoteOfferAnswer.SessionIDString())
+			for _, listener := range h.onNewOfferListeners {
+				listener(&remoteOfferAnswer)
+			}
+		case <-ctx.Done():
+			h.log.Infof("stop listening for remote offers and answers")
+			return
 		}
 	}
 }
@@ -101,43 +114,27 @@ func (h *Handshaker) SendOffer() error {
 
 // OnRemoteOffer handles an offer from the remote peer and returns true if the message was accepted, false otherwise
 // doesn't block, discards the message if connection wasn't ready
-func (h *Handshaker) OnRemoteOffer(offer OfferAnswer) bool {
+func (h *Handshaker) OnRemoteOffer(offer OfferAnswer) {
 	select {
 	case h.remoteOffersCh <- offer:
-		return true
+		return
 	default:
-		h.log.Warnf("OnRemoteOffer skipping message because is not ready")
+		h.log.Warnf("skipping remote offer message because receiver not ready")
 		// connection might not be ready yet to receive so we ignore the message
-		return false
+		return
 	}
 }
 
 // OnRemoteAnswer handles an offer from the remote peer and returns true if the message was accepted, false otherwise
 // doesn't block, discards the message if connection wasn't ready
-func (h *Handshaker) OnRemoteAnswer(answer OfferAnswer) bool {
+func (h *Handshaker) OnRemoteAnswer(answer OfferAnswer) {
 	select {
 	case h.remoteAnswerCh <- answer:
-		return true
+		return
 	default:
 		// connection might not be ready yet to receive so we ignore the message
-		h.log.Debugf("OnRemoteAnswer skipping message because is not ready")
-		return false
-	}
-}
-
-func (h *Handshaker) waitForRemoteOfferConfirmation(ctx context.Context) (*OfferAnswer, error) {
-	select {
-	case remoteOfferAnswer := <-h.remoteOffersCh:
-		// received confirmation from the remote peer -> ready to proceed
-		if err := h.sendAnswer(); err != nil {
-			return nil, err
-		}
-		return &remoteOfferAnswer, nil
-	case remoteOfferAnswer := <-h.remoteAnswerCh:
-		return &remoteOfferAnswer, nil
-	case <-ctx.Done():
-		// closed externally
-		return nil, NewConnectionClosedError(h.config.Key)
+		h.log.Warnf("skipping remote answer message because receiver not ready")
+		return
 	}
 }
 
@@ -147,43 +144,34 @@ func (h *Handshaker) sendOffer() error {
 		return ErrSignalIsNotReady
 	}
 
-	iceUFrag, icePwd := h.ice.GetLocalUserCredentials()
-	offer := OfferAnswer{
-		IceCredentials:  IceCredentials{iceUFrag, icePwd},
-		WgListenPort:    h.config.LocalWgPort,
-		Version:         version.NetbirdVersion(),
-		RosenpassPubKey: h.config.RosenpassConfig.PubKey,
-		RosenpassAddr:   h.config.RosenpassConfig.Addr,
-	}
-
-	addr, err := h.relay.RelayInstanceAddress()
-	if err == nil {
-		offer.RelaySrvAddress = addr
-	}
+	offer := h.buildOfferAnswer()
+	h.log.Infof("sending offer with serial: %s", offer.SessionIDString())
 
 	return h.signaler.SignalOffer(offer, h.config.Key)
 }
 
 func (h *Handshaker) sendAnswer() error {
-	h.log.Infof("sending answer")
-	uFrag, pwd := h.ice.GetLocalUserCredentials()
+	answer := h.buildOfferAnswer()
+	h.log.Infof("sending answer with serial: %s", answer.SessionIDString())
 
+	return h.signaler.SignalAnswer(answer, h.config.Key)
+}
+
+func (h *Handshaker) buildOfferAnswer() OfferAnswer {
+	uFrag, pwd := h.ice.GetLocalUserCredentials()
+	sid := h.ice.SessionID()
 	answer := OfferAnswer{
 		IceCredentials:  IceCredentials{uFrag, pwd},
 		WgListenPort:    h.config.LocalWgPort,
 		Version:         version.NetbirdVersion(),
 		RosenpassPubKey: h.config.RosenpassConfig.PubKey,
 		RosenpassAddr:   h.config.RosenpassConfig.Addr,
+		SessionID:       &sid,
 	}
-	addr, err := h.relay.RelayInstanceAddress()
-	if err == nil {
+
+	if addr, err := h.relay.RelayInstanceAddress(); err == nil {
 		answer.RelaySrvAddress = addr
 	}
 
-	err = h.signaler.SignalAnswer(answer, h.config.Key)
-	if err != nil {
-		return err
-	}
-
-	return nil
+	return answer
 }

client/internal/peer/ice/StunTurn.go

@@ -3,7 +3,7 @@ package ice
 import (
 	"sync/atomic"
 
-	"github.com/pion/stun/v2"
+	"github.com/pion/stun/v3"
 )
 
 type StunTurn atomic.Value

client/internal/peer/ice/agent.go

@@ -1,9 +1,10 @@
 package ice
 
 import (
+	"sync"
 	"time"
 
-	"github.com/pion/ice/v3"
+	"github.com/pion/ice/v4"
 	"github.com/pion/logging"
 	"github.com/pion/randutil"
 	log "github.com/sirupsen/logrus"
@@ -23,7 +24,20 @@ const (
 	iceRelayAcceptanceMinWaitDefault = 2 * time.Second
 )
 
-func NewAgent(iFaceDiscover stdnet.ExternalIFaceDiscover, config Config, candidateTypes []ice.CandidateType, ufrag string, pwd string) (*ice.Agent, error) {
+type ThreadSafeAgent struct {
+	*ice.Agent
+	once sync.Once
+}
+
+func (a *ThreadSafeAgent) Close() error {
+	var err error
+	a.once.Do(func() {
+		err = a.Agent.Close()
+	})
+	return err
+}
+
+func NewAgent(iFaceDiscover stdnet.ExternalIFaceDiscover, config Config, candidateTypes []ice.CandidateType, ufrag string, pwd string) (*ThreadSafeAgent, error) {
 	iceKeepAlive := iceKeepAlive()
 	iceDisconnectedTimeout := iceDisconnectedTimeout()
 	iceFailedTimeout := iceFailedTimeout()
@@ -61,7 +75,12 @@ func NewAgent(iFaceDiscover stdnet.ExternalIFaceDiscover, config Config, candida
 		agentConfig.NetworkTypes = []ice.NetworkType{ice.NetworkTypeUDP4}
 	}
 
-	return ice.NewAgent(agentConfig)
+	agent, err := ice.NewAgent(agentConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ThreadSafeAgent{Agent: agent}, nil
 }
 
 func GenerateICECredentials() (string, string, error) {

client/internal/peer/ice/config.go

@@ -1,7 +1,7 @@
 package ice
 
 import (
-	"github.com/pion/ice/v3"
+	"github.com/pion/ice/v4"
 )
 
 type Config struct {

client/internal/peer/session_id.go

@@ -0,0 +1,47 @@
+package peer
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"fmt"
+	"io"
+)
+
+const sessionIDSize = 5
+
+type ICESessionID string
+
+// NewICESessionID generates a new session ID for distinguishing sessions
+func NewICESessionID() (ICESessionID, error) {
+	b := make([]byte, sessionIDSize)
+	if _, err := io.ReadFull(rand.Reader, b); err != nil {
+		return "", fmt.Errorf("failed to generate session ID: %w", err)
+	}
+	return ICESessionID(hex.EncodeToString(b)), nil
+}
+
+func ICESessionIDFromBytes(b []byte) (ICESessionID, error) {
+	if len(b) != sessionIDSize {
+		return "", fmt.Errorf("invalid session ID length: %d", len(b))
+	}
+	return ICESessionID(hex.EncodeToString(b)), nil
+}
+
+// Bytes returns the raw bytes of the session ID for protobuf serialization
+func (id ICESessionID) Bytes() ([]byte, error) {
+	if len(id) == 0 {
+		return nil, fmt.Errorf("ICE session ID is empty")
+	}
+	b, err := hex.DecodeString(string(id))
+	if err != nil {
+		return nil, fmt.Errorf("invalid ICE session ID encoding: %w", err)
+	}
+	if len(b) != sessionIDSize {
+		return nil, fmt.Errorf("invalid ICE session ID length: expected %d bytes, got %d", sessionIDSize, len(b))
+	}
+	return b, nil
+}
+
+func (id ICESessionID) String() string {
+	return string(id)
+}

client/internal/peer/signaler.go

@@ -1,7 +1,8 @@
 package peer
 
 import (
-	"github.com/pion/ice/v3"
+	"github.com/pion/ice/v4"
+	log "github.com/sirupsen/logrus"
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 
 	signal "github.com/netbirdio/netbird/shared/signal/client"
@@ -45,6 +46,10 @@ func (s *Signaler) Ready() bool {
 
 // SignalOfferAnswer signals either an offer or an answer to remote peer
 func (s *Signaler) signalOfferAnswer(offerAnswer OfferAnswer, remoteKey string, bodyType sProto.Body_Type) error {
+	sessionIDBytes, err := offerAnswer.SessionID.Bytes()
+	if err != nil {
+		log.Warnf("failed to get session ID bytes: %v", err)
+	}
 	msg, err := signal.MarshalCredential(
 		s.wgPrivateKey,
 		offerAnswer.WgListenPort,
@@ -56,13 +61,13 @@ func (s *Signaler) signalOfferAnswer(offerAnswer OfferAnswer, remoteKey string,
 		bodyType,
 		offerAnswer.RosenpassPubKey,
 		offerAnswer.RosenpassAddr,
-		offerAnswer.RelaySrvAddress)
+		offerAnswer.RelaySrvAddress,
+		sessionIDBytes)
 	if err != nil {
 		return err
 	}
 
-	err = s.signal.Send(msg)
-	if err != nil {
+	if err = s.signal.Send(msg); err != nil {
 		return err
 	}
 

client/internal/peer/worker_ice.go

@@ -8,7 +8,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/pion/ice/v3"
+	"github.com/pion/ice/v4"
 	"github.com/pion/stun/v2"
 	log "github.com/sirupsen/logrus"
 
@@ -42,8 +42,18 @@ type WorkerICE struct {
 	statusRecorder    *Status
 	hasRelayOnLocally bool
 
-	agent    *ice.Agent
-	muxAgent sync.Mutex
+	agent             *icemaker.ThreadSafeAgent
+	agentDialerCancel context.CancelFunc
+	agentConnecting   bool      // while it is true, drop all incoming offers
+	lastSuccess       time.Time // with this avoid the too frequent ICE agent recreation
+	// remoteSessionID represents the peer's session identifier from the latest remote offer.
+	remoteSessionID ICESessionID
+	// sessionID is used to track the current session ID of the ICE agent
+	// increase by one when disconnecting the agent
+	// with it the remote peer can discard the already deprecated offer/answer
+	// Without it the remote peer may recreate a workable ICE connection
+	sessionID ICESessionID
+	muxAgent  sync.Mutex
 
 	StunTurn []*stun.URI
 
@@ -57,6 +67,11 @@ type WorkerICE struct {
 }
 
 func NewWorkerICE(ctx context.Context, log *log.Entry, config ConnConfig, conn *Conn, signaler *Signaler, ifaceDiscover stdnet.ExternalIFaceDiscover, statusRecorder *Status, hasRelayOnLocally bool) (*WorkerICE, error) {
+	sessionID, err := NewICESessionID()
+	if err != nil {
+		return nil, err
+	}
+
 	w := &WorkerICE{
 		ctx:               ctx,
 		log:               log,
@@ -67,6 +82,7 @@ func NewWorkerICE(ctx context.Context, log *log.Entry, config ConnConfig, conn *
 		statusRecorder:    statusRecorder,
 		hasRelayOnLocally: hasRelayOnLocally,
 		lastKnownState:    ice.ConnectionStateDisconnected,
+		sessionID:         sessionID,
 	}
 
 	localUfrag, localPwd, err := icemaker.GenerateICECredentials()
@@ -79,15 +95,36 @@ func NewWorkerICE(ctx context.Context, log *log.Entry, config ConnConfig, conn *
 }
 
 func (w *WorkerICE) OnNewOffer(remoteOfferAnswer *OfferAnswer) {
-	w.log.Debugf("OnNewOffer for ICE")
+	w.log.Debugf("OnNewOffer for ICE, serial: %s", remoteOfferAnswer.SessionIDString())
 	w.muxAgent.Lock()
 
-	if w.agent != nil {
-		w.log.Debugf("agent already exists, skipping the offer")
+	if w.agentConnecting {
+		w.log.Debugf("agent connection is in progress, skipping the offer")
 		w.muxAgent.Unlock()
 		return
 	}
 
+	if w.agent != nil {
+		// backward compatibility with old clients that do not send session ID
+		if remoteOfferAnswer.SessionID == nil {
+			w.log.Debugf("agent already exists, skipping the offer")
+			w.muxAgent.Unlock()
+			return
+		}
+		if w.remoteSessionID == *remoteOfferAnswer.SessionID {
+			w.log.Debugf("agent already exists and session ID matches, skipping the offer: %s", remoteOfferAnswer.SessionIDString())
+			w.muxAgent.Unlock()
+			return
+		}
+		w.log.Debugf("agent already exists, recreate the connection")
+		w.agentDialerCancel()
+		if err := w.agent.Close(); err != nil {
+			w.log.Warnf("failed to close ICE agent: %s", err)
+		}
+		w.agent = nil
+		// todo consider to switch to Relay connection while establishing a new ICE connection
+	}
+
 	var preferredCandidateTypes []ice.CandidateType
 	if w.hasRelayOnLocally && remoteOfferAnswer.RelaySrvAddress != "" {
 		preferredCandidateTypes = icemaker.CandidateTypesP2P()
@@ -96,36 +133,125 @@ func (w *WorkerICE) OnNewOffer(remoteOfferAnswer *OfferAnswer) {
 	}
 
 	w.log.Debugf("recreate ICE agent")
-	agentCtx, agentCancel := context.WithCancel(w.ctx)
-	agent, err := w.reCreateAgent(agentCancel, preferredCandidateTypes)
+	dialerCtx, dialerCancel := context.WithCancel(w.ctx)
+	agent, err := w.reCreateAgent(dialerCancel, preferredCandidateTypes)
 	if err != nil {
 		w.log.Errorf("failed to recreate ICE Agent: %s", err)
 		w.muxAgent.Unlock()
 		return
 	}
+	w.sentExtraSrflx = false
 	w.agent = agent
+	w.agentDialerCancel = dialerCancel
+	w.agentConnecting = true
 	w.muxAgent.Unlock()
 
-	w.log.Debugf("gather candidates")
-	err = w.agent.GatherCandidates()
-	if err != nil {
-		w.log.Debugf("failed to gather candidates: %s", err)
+	go w.connect(dialerCtx, agent, remoteOfferAnswer)
+}
+
+// OnRemoteCandidate Handles ICE connection Candidate provided by the remote peer.
+func (w *WorkerICE) OnRemoteCandidate(candidate ice.Candidate, haRoutes route.HAMap) {
+	w.muxAgent.Lock()
+	defer w.muxAgent.Unlock()
+	w.log.Debugf("OnRemoteCandidate from peer %s -> %s", w.config.Key, candidate.String())
+	if w.agent == nil {
+		w.log.Warnf("ICE Agent is not initialized yet")
+		return
+	}
+
+	if candidateViaRoutes(candidate, haRoutes) {
+		return
+	}
+
+	if err := w.agent.AddRemoteCandidate(candidate); err != nil {
+		w.log.Errorf("error while handling remote candidate")
+		return
+	}
+}
+
+func (w *WorkerICE) GetLocalUserCredentials() (frag string, pwd string) {
+	return w.localUfrag, w.localPwd
+}
+
+func (w *WorkerICE) InProgress() bool {
+	w.muxAgent.Lock()
+	defer w.muxAgent.Unlock()
+
+	return w.agentConnecting
+}
+
+func (w *WorkerICE) Close() {
+	w.muxAgent.Lock()
+	defer w.muxAgent.Unlock()
+
+	if w.agent == nil {
+		return
+	}
+
+	w.agentDialerCancel()
+	if err := w.agent.Close(); err != nil {
+		w.log.Warnf("failed to close ICE agent: %s", err)
+	}
+
+	w.agent = nil
+}
+
+func (w *WorkerICE) reCreateAgent(dialerCancel context.CancelFunc, candidates []ice.CandidateType) (*icemaker.ThreadSafeAgent, error) {
+	agent, err := icemaker.NewAgent(w.iFaceDiscover, w.config.ICEConfig, candidates, w.localUfrag, w.localPwd)
+	if err != nil {
+		return nil, fmt.Errorf("create agent: %w", err)
+	}
+
+	if err := agent.OnCandidate(w.onICECandidate); err != nil {
+		return nil, err
+	}
+
+	if err := agent.OnConnectionStateChange(w.onConnectionStateChange(agent, dialerCancel)); err != nil {
+		return nil, err
+	}
+
+	if err := agent.OnSelectedCandidatePairChange(w.onICESelectedCandidatePair); err != nil {
+		return nil, err
+	}
+
+	return agent, nil
+}
+
+func (w *WorkerICE) SessionID() ICESessionID {
+	w.muxAgent.Lock()
+	defer w.muxAgent.Unlock()
+
+	return w.sessionID
+}
+
+// will block until connection succeeded
+// but it won't release if ICE Agent went into Disconnected or Failed state,
+// so we have to cancel it with the provided context once agent detected a broken connection
+func (w *WorkerICE) connect(ctx context.Context, agent *icemaker.ThreadSafeAgent, remoteOfferAnswer *OfferAnswer) {
+	w.log.Debugf("gather candidates")
+	if err := agent.GatherCandidates(); err != nil {
+		w.log.Warnf("failed to gather candidates: %s", err)
+		w.closeAgent(agent, w.agentDialerCancel)
 		return
 	}
 
-	// will block until connection succeeded
-	// but it won't release if ICE Agent went into Disconnected or Failed state,
-	// so we have to cancel it with the provided context once agent detected a broken connection
 	w.log.Debugf("turn agent dial")
-	remoteConn, err := w.turnAgentDial(agentCtx, remoteOfferAnswer)
+	remoteConn, err := w.turnAgentDial(ctx, agent, remoteOfferAnswer)
 	if err != nil {
 		w.log.Debugf("failed to dial the remote peer: %s", err)
+		w.closeAgent(agent, w.agentDialerCancel)
 		return
 	}
 	w.log.Debugf("agent dial succeeded")
 
-	pair, err := w.agent.GetSelectedCandidatePair()
+	pair, err := agent.GetSelectedCandidatePair()
 	if err != nil {
+		w.closeAgent(agent, w.agentDialerCancel)
+		return
+	}
+	if pair == nil {
+		w.log.Warnf("selected candidate pair is nil, cannot proceed")
+		w.closeAgent(agent, w.agentDialerCancel)
 		return
 	}
 
@@ -152,114 +278,39 @@ func (w *WorkerICE) OnNewOffer(remoteOfferAnswer *OfferAnswer) {
 		RelayedOnLocal:             isRelayCandidate(pair.Local),
 	}
 	w.log.Debugf("on ICE conn is ready to use")
-	go w.conn.onICEConnectionIsReady(selectedPriority(pair), ci)
-}
 
-// OnRemoteCandidate Handles ICE connection Candidate provided by the remote peer.
-func (w *WorkerICE) OnRemoteCandidate(candidate ice.Candidate, haRoutes route.HAMap) {
+	w.log.Infof("connection succeeded with offer session: %s", remoteOfferAnswer.SessionIDString())
 	w.muxAgent.Lock()
-	defer w.muxAgent.Unlock()
-	w.log.Debugf("OnRemoteCandidate from peer %s -> %s", w.config.Key, candidate.String())
-	if w.agent == nil {
-		w.log.Warnf("ICE Agent is not initialized yet")
-		return
+	w.agentConnecting = false
+	w.lastSuccess = time.Now()
+	if remoteOfferAnswer.SessionID != nil {
+		w.remoteSessionID = *remoteOfferAnswer.SessionID
 	}
+	w.muxAgent.Unlock()
 
-	if candidateViaRoutes(candidate, haRoutes) {
-		return
-	}
-
-	err := w.agent.AddRemoteCandidate(candidate)
-	if err != nil {
-		w.log.Errorf("error while handling remote candidate")
-		return
-	}
+	// todo: the potential problem is a race between the onConnectionStateChange
+	w.conn.onICEConnectionIsReady(selectedPriority(pair), ci)
 }
 
-func (w *WorkerICE) GetLocalUserCredentials() (frag string, pwd string) {
-	w.muxAgent.Lock()
-	defer w.muxAgent.Unlock()
-	return w.localUfrag, w.localPwd
-}
-
-func (w *WorkerICE) Close() {
-	w.muxAgent.Lock()
-	defer w.muxAgent.Unlock()
-
-	if w.agent == nil {
-		return
-	}
-
-	if err := w.agent.Close(); err != nil {
-		w.log.Warnf("failed to close ICE agent: %s", err)
-	}
-}
-
-func (w *WorkerICE) reCreateAgent(agentCancel context.CancelFunc, candidates []ice.CandidateType) (*ice.Agent, error) {
-	w.sentExtraSrflx = false
-
-	agent, err := icemaker.NewAgent(w.iFaceDiscover, w.config.ICEConfig, candidates, w.localUfrag, w.localPwd)
-	if err != nil {
-		return nil, fmt.Errorf("create agent: %w", err)
-	}
-
-	err = agent.OnCandidate(w.onICECandidate)
-	if err != nil {
-		return nil, err
-	}
-
-	err = agent.OnConnectionStateChange(func(state ice.ConnectionState) {
-		w.log.Debugf("ICE ConnectionState has changed to %s", state.String())
-		switch state {
-		case ice.ConnectionStateConnected:
-			w.lastKnownState = ice.ConnectionStateConnected
-			return
-		case ice.ConnectionStateFailed, ice.ConnectionStateDisconnected:
-			if w.lastKnownState == ice.ConnectionStateConnected {
-				w.lastKnownState = ice.ConnectionStateDisconnected
-				w.conn.onICEStateDisconnected()
-			}
-			w.closeAgent(agentCancel)
-		default:
-			return
-		}
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	err = agent.OnSelectedCandidatePairChange(w.onICESelectedCandidatePair)
-	if err != nil {
-		return nil, err
-	}
-
-	err = agent.OnSuccessfulSelectedPairBindingResponse(func(p *ice.CandidatePair) {
-		err := w.statusRecorder.UpdateLatency(w.config.Key, p.Latency())
-		if err != nil {
-			w.log.Debugf("failed to update latency for peer: %s", err)
-			return
-		}
-	})
-	if err != nil {
-		return nil, fmt.Errorf("failed setting binding response callback: %w", err)
-	}
-
-	return agent, nil
-}
-
-func (w *WorkerICE) closeAgent(cancel context.CancelFunc) {
-	w.muxAgent.Lock()
-	defer w.muxAgent.Unlock()
-
+func (w *WorkerICE) closeAgent(agent *icemaker.ThreadSafeAgent, cancel context.CancelFunc) {
 	cancel()
-	if w.agent == nil {
-		return
-	}
-
-	if err := w.agent.Close(); err != nil {
+	if err := agent.Close(); err != nil {
 		w.log.Warnf("failed to close ICE agent: %s", err)
 	}
-	w.agent = nil
+
+	w.muxAgent.Lock()
+	// todo review does it make sense to generate new session ID all the time when w.agent==agent
+	sessionID, err := NewICESessionID()
+	if err != nil {
+		w.log.Errorf("failed to create new session ID: %s", err)
+	}
+	w.sessionID = sessionID
+
+	if w.agent == agent {
+		w.agent = nil
+		w.agentConnecting = false
+	}
+	w.muxAgent.Unlock()
 }
 
 func (w *WorkerICE) punchRemoteWGPort(pair *ice.CandidatePair, remoteWgPort int) {
@@ -329,6 +380,46 @@ func (w *WorkerICE) onICECandidate(candidate ice.Candidate) {
 func (w *WorkerICE) onICESelectedCandidatePair(c1 ice.Candidate, c2 ice.Candidate) {
 	w.log.Debugf("selected candidate pair [local <-> remote] -> [%s <-> %s], peer %s", c1.String(), c2.String(),
 		w.config.Key)
+
+	w.muxAgent.Lock()
+
+	pair, err := w.agent.GetSelectedCandidatePair()
+	if err != nil {
+		w.log.Warnf("failed to get selected candidate pair: %s", err)
+		w.muxAgent.Unlock()
+		return
+	}
+	if pair == nil {
+		w.log.Warnf("selected candidate pair is nil, cannot proceed")
+		w.muxAgent.Unlock()
+		return
+	}
+	w.muxAgent.Unlock()
+
+	duration := time.Duration(pair.CurrentRoundTripTime() * float64(time.Second))
+	if err := w.statusRecorder.UpdateLatency(w.config.Key, duration); err != nil {
+		w.log.Debugf("failed to update latency for peer: %s", err)
+		return
+	}
+}
+
+func (w *WorkerICE) onConnectionStateChange(agent *icemaker.ThreadSafeAgent, dialerCancel context.CancelFunc) func(ice.ConnectionState) {
+	return func(state ice.ConnectionState) {
+		w.log.Debugf("ICE ConnectionState has changed to %s", state.String())
+		switch state {
+		case ice.ConnectionStateConnected:
+			w.lastKnownState = ice.ConnectionStateConnected
+			return
+		case ice.ConnectionStateFailed, ice.ConnectionStateDisconnected:
+			if w.lastKnownState == ice.ConnectionStateConnected {
+				w.lastKnownState = ice.ConnectionStateDisconnected
+				w.conn.onICEStateDisconnected()
+			}
+			w.closeAgent(agent, dialerCancel)
+		default:
+			return
+		}
+	}
 }
 
 func (w *WorkerICE) shouldSendExtraSrflxCandidate(candidate ice.Candidate) bool {
@@ -338,18 +429,18 @@ func (w *WorkerICE) shouldSendExtraSrflxCandidate(candidate ice.Candidate) bool
 	return false
 }
 
-func (w *WorkerICE) turnAgentDial(ctx context.Context, remoteOfferAnswer *OfferAnswer) (*ice.Conn, error) {
+func (w *WorkerICE) turnAgentDial(ctx context.Context, agent *icemaker.ThreadSafeAgent, remoteOfferAnswer *OfferAnswer) (*ice.Conn, error) {
 	isControlling := w.config.LocalKey > w.config.Key
 	if isControlling {
-		return w.agent.Dial(ctx, remoteOfferAnswer.IceCredentials.UFrag, remoteOfferAnswer.IceCredentials.Pwd)
+		return agent.Dial(ctx, remoteOfferAnswer.IceCredentials.UFrag, remoteOfferAnswer.IceCredentials.Pwd)
 	} else {
-		return w.agent.Accept(ctx, remoteOfferAnswer.IceCredentials.UFrag, remoteOfferAnswer.IceCredentials.Pwd)
+		return agent.Accept(ctx, remoteOfferAnswer.IceCredentials.UFrag, remoteOfferAnswer.IceCredentials.Pwd)
 	}
 }
 
 func extraSrflxCandidate(candidate ice.Candidate) (*ice.CandidateServerReflexive, error) {
 	relatedAdd := candidate.RelatedAddress()
-	return ice.NewCandidateServerReflexive(&ice.CandidateServerReflexiveConfig{
+	ec, err := ice.NewCandidateServerReflexive(&ice.CandidateServerReflexiveConfig{
 		Network:   candidate.NetworkType().String(),
 		Address:   candidate.Address(),
 		Port:      relatedAdd.Port,
@@ -357,6 +448,17 @@ func extraSrflxCandidate(candidate ice.Candidate) (*ice.CandidateServerReflexive
 		RelAddr:   relatedAdd.Address,
 		RelPort:   relatedAdd.Port,
 	})
+	if err != nil {
+		return nil, err
+	}
+
+	for _, e := range candidate.Extensions() {
+		if err := ec.AddExtension(e); err != nil {
+			return nil, err
+		}
+	}
+
+	return ec, nil
 }
 
 func candidateViaRoutes(candidate ice.Candidate, clientRoutes route.HAMap) bool {

client/internal/profilemanager/config.go

@@ -75,6 +75,8 @@ type ConfigInput struct {
 	DNSLabels domain.List
 
 	LazyConnectionEnabled *bool
+
+	MTU *uint16
 }
 
 // Config Configuration type
@@ -141,6 +143,8 @@ type Config struct {
 	ClientCertKeyPair *tls.Certificate `json:"-"`
 
 	LazyConnectionEnabled bool
+
+	MTU uint16
 }
 
 var ConfigDirOverride string
@@ -493,6 +497,16 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		updated = true
 	}
 
+	if input.MTU != nil && *input.MTU != config.MTU {
+		log.Infof("updating MTU to %d (old value %d)", *input.MTU, config.MTU)
+		config.MTU = *input.MTU
+		updated = true
+	} else if config.MTU == 0 {
+		config.MTU = iface.DefaultMTU
+		log.Infof("using default MTU %d", config.MTU)
+		updated = true
+	}
+
 	return updated, nil
 }
 

client/internal/relay/relay.go

@@ -7,7 +7,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/pion/stun/v2"
+	"github.com/pion/stun/v3"
 	"github.com/pion/turn/v3"
 	log "github.com/sirupsen/logrus"
 

client/internal/routemanager/dnsinterceptor/handler.go

@@ -2,11 +2,13 @@ package dnsinterceptor
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"net/netip"
 	"runtime"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/hashicorp/go-multierror"
 	"github.com/miekg/dns"
@@ -26,6 +28,8 @@ import (
 	"github.com/netbirdio/netbird/route"
 )
 
+const dnsTimeout = 8 * time.Second
+
 type domainMap map[domain.Domain][]netip.Prefix
 
 type internalDNATer interface {
@@ -243,7 +247,7 @@ func (d *DnsInterceptor) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 		return
 	}
 
-	client, err := nbdns.GetClientPrivate(d.wgInterface.Address().IP, d.wgInterface.Name(), nbdns.UpstreamTimeout)
+	client, err := nbdns.GetClientPrivate(d.wgInterface.Address().IP, d.wgInterface.Name(), dnsTimeout)
 	if err != nil {
 		d.writeDNSError(w, r, logger, fmt.Sprintf("create DNS client: %v", err))
 		return
@@ -254,9 +258,20 @@ func (d *DnsInterceptor) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	}
 
 	upstream := fmt.Sprintf("%s:%d", upstreamIP.String(), dnsfwd.ListenPort)
-	reply, _, err := nbdns.ExchangeWithFallback(context.TODO(), client, r, upstream)
+	ctx, cancel := context.WithTimeout(context.Background(), dnsTimeout)
+	defer cancel()
+
+	startTime := time.Now()
+	reply, _, err := nbdns.ExchangeWithFallback(ctx, client, r, upstream)
 	if err != nil {
-		logger.Errorf("failed to exchange DNS request with %s (%s) for domain=%s: %v", upstreamIP.String(), peerKey, r.Question[0].Name, err)
+		if errors.Is(err, context.DeadlineExceeded) {
+			elapsed := time.Since(startTime)
+			peerInfo := d.debugPeerTimeout(upstreamIP, peerKey)
+			logger.Errorf("peer DNS timeout after %v (timeout=%v) for domain=%s to peer %s (%s)%s - error: %v",
+				elapsed.Truncate(time.Millisecond), dnsTimeout, r.Question[0].Name, upstreamIP.String(), peerKey, peerInfo, err)
+		} else {
+			logger.Errorf("failed to exchange DNS request with %s (%s) for domain=%s: %v", upstreamIP.String(), peerKey, r.Question[0].Name, err)
+		}
 		if err := w.WriteMsg(&dns.Msg{MsgHdr: dns.MsgHdr{Rcode: dns.RcodeServerFailure, Id: r.Id}}); err != nil {
 			logger.Errorf("failed writing DNS response: %v", err)
 		}
@@ -568,3 +583,16 @@ func determinePrefixChanges(oldPrefixes, newPrefixes []netip.Prefix) (toAdd, toR
 	}
 	return
 }
+
+func (d *DnsInterceptor) debugPeerTimeout(peerIP netip.Addr, peerKey string) string {
+	if d.statusRecorder == nil {
+		return ""
+	}
+
+	peerState, err := d.statusRecorder.GetPeer(peerKey)
+	if err != nil {
+		return fmt.Sprintf(" (peer %s state error: %v)", peerKey[:8], err)
+	}
+
+	return fmt.Sprintf(" (peer %s)", nbdns.FormatPeerStatus(&peerState))
+}

client/internal/routemanager/manager.go

@@ -36,8 +36,8 @@ import (
 	"github.com/netbirdio/netbird/client/internal/routemanager/vars"
 	"github.com/netbirdio/netbird/client/internal/routeselector"
 	"github.com/netbirdio/netbird/client/internal/statemanager"
-	relayClient "github.com/netbirdio/netbird/shared/relay/client"
 	"github.com/netbirdio/netbird/route"
+	relayClient "github.com/netbirdio/netbird/shared/relay/client"
 	nbnet "github.com/netbirdio/netbird/util/net"
 	"github.com/netbirdio/netbird/version"
 )
@@ -368,7 +368,11 @@ func (m *DefaultManager) UpdateRoutes(
 
 	var merr *multierror.Error
 	if !m.disableClientRoutes {
-		filteredClientRoutes := m.routeSelector.FilterSelected(clientRoutes)
+
+		// Update route selector based on management server's isSelected status
+		m.updateRouteSelectorFromManagement(clientRoutes)
+
+		filteredClientRoutes := m.routeSelector.FilterSelectedExitNodes(clientRoutes)
 
 		if err := m.updateSystemRoutes(filteredClientRoutes); err != nil {
 			merr = multierror.Append(merr, fmt.Errorf("update system routes: %w", err))
@@ -430,7 +434,7 @@ func (m *DefaultManager) TriggerSelection(networks route.HAMap) {
 	m.mux.Lock()
 	defer m.mux.Unlock()
 
-	networks = m.routeSelector.FilterSelected(networks)
+	networks = m.routeSelector.FilterSelectedExitNodes(networks)
 
 	m.notifier.OnNewRoutes(networks)
 
@@ -583,3 +587,106 @@ func resolveURLsToIPs(urls []string) []net.IP {
 	}
 	return ips
 }
+
+// updateRouteSelectorFromManagement updates the route selector based on the isSelected status from the management server
+func (m *DefaultManager) updateRouteSelectorFromManagement(clientRoutes route.HAMap) {
+	exitNodeInfo := m.collectExitNodeInfo(clientRoutes)
+	if len(exitNodeInfo.allIDs) == 0 {
+		return
+	}
+
+	m.updateExitNodeSelections(exitNodeInfo)
+	m.logExitNodeUpdate(exitNodeInfo)
+}
+
+type exitNodeInfo struct {
+	allIDs               []route.NetID
+	selectedByManagement []route.NetID
+	userSelected         []route.NetID
+	userDeselected       []route.NetID
+}
+
+func (m *DefaultManager) collectExitNodeInfo(clientRoutes route.HAMap) exitNodeInfo {
+	var info exitNodeInfo
+
+	for haID, routes := range clientRoutes {
+		if !m.isExitNodeRoute(routes) {
+			continue
+		}
+
+		netID := haID.NetID()
+		info.allIDs = append(info.allIDs, netID)
+
+		if m.routeSelector.HasUserSelectionForRoute(netID) {
+			m.categorizeUserSelection(netID, &info)
+		} else {
+			m.checkManagementSelection(routes, netID, &info)
+		}
+	}
+
+	return info
+}
+
+func (m *DefaultManager) isExitNodeRoute(routes []*route.Route) bool {
+	return len(routes) > 0 && routes[0].Network.String() == vars.ExitNodeCIDR
+}
+
+func (m *DefaultManager) categorizeUserSelection(netID route.NetID, info *exitNodeInfo) {
+	if m.routeSelector.IsSelected(netID) {
+		info.userSelected = append(info.userSelected, netID)
+	} else {
+		info.userDeselected = append(info.userDeselected, netID)
+	}
+}
+
+func (m *DefaultManager) checkManagementSelection(routes []*route.Route, netID route.NetID, info *exitNodeInfo) {
+	for _, route := range routes {
+		if !route.SkipAutoApply {
+			info.selectedByManagement = append(info.selectedByManagement, netID)
+			break
+		}
+	}
+}
+
+func (m *DefaultManager) updateExitNodeSelections(info exitNodeInfo) {
+	routesToDeselect := m.getRoutesToDeselect(info.allIDs)
+	m.deselectExitNodes(routesToDeselect)
+	m.selectExitNodesByManagement(info.selectedByManagement, info.allIDs)
+}
+
+func (m *DefaultManager) getRoutesToDeselect(allIDs []route.NetID) []route.NetID {
+	var routesToDeselect []route.NetID
+	for _, netID := range allIDs {
+		if !m.routeSelector.HasUserSelectionForRoute(netID) {
+			routesToDeselect = append(routesToDeselect, netID)
+		}
+	}
+	return routesToDeselect
+}
+
+func (m *DefaultManager) deselectExitNodes(routesToDeselect []route.NetID) {
+	if len(routesToDeselect) == 0 {
+		return
+	}
+
+	err := m.routeSelector.DeselectRoutes(routesToDeselect, routesToDeselect)
+	if err != nil {
+		log.Warnf("Failed to deselect exit nodes: %v", err)
+	}
+}
+
+func (m *DefaultManager) selectExitNodesByManagement(selectedByManagement []route.NetID, allIDs []route.NetID) {
+	if len(selectedByManagement) == 0 {
+		return
+	}
+
+	err := m.routeSelector.SelectRoutes(selectedByManagement, true, allIDs)
+	if err != nil {
+		log.Warnf("Failed to select exit nodes: %v", err)
+	}
+}
+
+func (m *DefaultManager) logExitNodeUpdate(info exitNodeInfo) {
+	log.Debugf("Updated route selector: %d exit nodes available, %d selected by management, %d user-selected, %d user-deselected",
+		len(info.allIDs), len(info.selectedByManagement), len(info.userSelected), len(info.userDeselected))
+}

client/internal/routemanager/manager_test.go

@@ -190,14 +190,15 @@ func TestManagerUpdateRoutes(t *testing.T) {
 			name: "No Small Client Route Should Be Added",
 			inputRoutes: []*route.Route{
 				{
-					ID:          "a",
-					NetID:       "routeA",
-					Peer:        remotePeerKey1,
-					Network:     netip.MustParsePrefix("0.0.0.0/0"),
-					NetworkType: route.IPv4Network,
-					Metric:      9999,
-					Masquerade:  false,
-					Enabled:     true,
+					ID:            "a",
+					NetID:         "routeA",
+					Peer:          remotePeerKey1,
+					Network:       netip.MustParsePrefix("0.0.0.0/0"),
+					NetworkType:   route.IPv4Network,
+					Metric:        9999,
+					Masquerade:    false,
+					Enabled:       true,
+					SkipAutoApply: false,
 				},
 			},
 			inputSerial:                          1,

client/internal/routemanager/systemops/systemops_windows.go

@@ -336,7 +336,7 @@ func createIPForwardEntry2(route *MIB_IPFORWARD_ROW2) error {
 		if e1 != 0 {
 			return fmt.Errorf("CreateIpForwardEntry2: %w", e1)
 		}
-		return fmt.Errorf("CreateIpForwardEntry2: code %d", r1)
+		return fmt.Errorf("CreateIpForwardEntry2: code %d", windows.NTStatus(r1))
 	}
 	return nil
 }

client/internal/routemanager/vars/vars.go

@@ -13,4 +13,6 @@ var (
 
 	Defaultv4 = netip.PrefixFrom(netip.IPv4Unspecified(), 0)
 	Defaultv6 = netip.PrefixFrom(netip.IPv6Unspecified(), 0)
+
+	ExitNodeCIDR = "0.0.0.0/0"
 )